Physics Study Guide
Second Trimester Exam (March 13)
The second trimester exam will ask 80 multiple-choice questions (1 Point Each)
and 10 math-based problems out of which you are required to pick any 8 (2.5
Points Each) from chapters 9 thru 19. Questions will be based on this study
guide.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
____
____
____
____
____
1. Which of the following is NOT a unit of rotational speed?
a. Meters per second
b. Revolutions per minute
c. Revolutions per second
d. Rotations per second
e. Rotations per minute
2. What is the direction of the force that acts on clothes in the spin cycle of a washing machine?
a. Inward
b. Down
c. Outward
d. Up
3. A tin can whirled on the end of a string moves in a circle because
a. the can continually pulls on the string.
b. once the can starts moving, that is its natural tendency.
c. there is a force on the can pulling it outward.
d. there is an inward force acting on the can.
e. all of the above
4. A ladybug rests on the bottom of a tin can that is being whirled horizontally on the end of a
string. Since the ladybug, like the can, moves in a circle, there must be a force on it. What exerts
this force?
a. Gravity
b. The string
c. There is no force acting on it.
d. The can
e. Your hand
5. People in the future may well live inside a rotating space structure that is more than 2 km in
diameter. Inside the structure, people on the inside of the outer edge will experience 1 g while
people halfway to the axis will experience
a. 2 g.
b. 1 g.
c.
g.
d.
g.
e. 0 g.
6. "Centrifugal forces" are an apparent reality to observers in a reference frame that is
a. rotating.
b. an inertial reference frame.
c. moving at constant velocity.
____
7.
____
8.
____
9.
____ 10.
____ 11.
____ 12.
____ 13.
____ 14.
d. at rest.
e. none of the above
A person weighs less at the equator than at the poles. The reason for this has to do with the
a. tidal bulges.
b. influence of the sun, moon, and all the planets.
c. higher temperature at the equator, and expansion of matter.
d. spin of the Earth.
e. none of the above
As the rotational speed of a space habitat increases, the weight of people inside
a. decreases.
b. increases.
c. stays the same.
If Earth rotated more slowly about its axis, your weight would
a. decrease.
b. increase.
c. stay the same.
To weigh less in the Northern Hemisphere, you should go
a. west.
b. east.
c. south.
d. north.
A possible space habitat of the future is a cylinder in space rotating about its long axis. What is
the relative gravitational field along the axis of the habitat?
a. One-quarter g
b. One-half g
c. Three-quarters g
d. g
e. Zero
When a railroad train rounds a banked track, the centripetal force needed comes not from friction,
but from the
a. vertical component of the normal force.
b. horizontal component of the normal force.
c. normal force.
d. none of the above
The centripetal force exerted on stunt motorcyclist Biker Bob while riding on the inner vertical
surface of a circular track is
a. friction.
b. his weight.
c. the normal force.
d. none of the above
Nellie Newton swings a rock into a circular path while holding an attached string overhead. The
string makes a 45-degree angle to the vertical (comprising a "conical pendulum"). The centripetal
force that holds the rock in its circular path is the
a. vertical component of the string tension.
b. horizontal component of the string tension.
c. tension in the string.
d. none of the above
____ 15. Stunt motorcyclist Biker Bob rides his bike inside a futuristic rotating space station-a giant
rotating donut-shaped structure in space. The normal support force feels like weight to him. As he
rides his bike in the same direction that the station rotates, the normal force
a. remains unaffected.
b. increases.
c. decreases.
____ 16. Stunt motorcyclist Biker Bob rides his bike inside a futuristic rotating space station—a giant
rotating donut-shaped structure in space. The normal support force feels like weight to him. As he
rides his bike in the opposite direction to the station’s rotation, the normal force
a. remains unaffected.
b. increases.
c. decreases.
____ 17. Suzie Spacewalker hovers in space beside a rotating space station in outer space. Both she and the
center of mass of the space station are at relative rest. If the space station is in Earth orbit, then
Suzie
a. is also in Earth orbit.
b. is not in Earth orbit.
c. may or may not be in Earth orbit.
____ 18. A space habitat is designed so that the variation in g between a person's head and feet is less than
0.01 g. If the person is 2 m tall, then the radius of the habitat is
a. 20 m.
b. 200 m.
c. 2000 m.
d. more than 2000 m.
____ 19. The center of gravity of an object can be located by
a. balancing it above your finger.
b. looking at the intersection of lines drawn straight down from suspension points.
c. all of the above
d. none of the above
____ 20. An object will fall over if its center of gravity is
a. outside the object.
b. too low.
c. not over its area of support.
d. too high.
____ 21. When you carry a heavy load with one arm, why do you tend to hold your free arm away from
your body?
a. To change the mass of your body
b. To be ready to grab something in case you fall
c. To look good
d. To change the center of gravity of your body and the load
e. To change the weight of your body and the load
____ 22. If an object is in stable equilibrium, any displacement will
a. raise its center of gravity.
b. neither raise nor lower its center of gravity.
c. decrease its mass.
d. increase its mass.
e. lower its center of gravity.
____ 23. If an object is in neutral equilibrium, any displacement will
a. raise its center of gravity.
b. decrease its mass.
c. increase its mass.
d. neither raise nor lower its center of gravity.
e. lower its center of gravity.
____ 24. The center of mass of the solar system
a. varies as the planets move.
b. is at the center of the sun.
c. neither A nor B
____ 25. If a plumb line is dropped from a suspension point of a rectangular sheet of plywood,
a. half the mass of the wood will be on either side of the line.
b. the line will pass through the center of gravity of the wood.
c. half the weight will be on either side of the line.
d. all of the above
e. none of the above
____ 26. A fish suspended in water is in what kind of equilibrium?
a. Neutral
b. Stable
c. Unstable
____ 27. A ball resting on the floor is in what kind of equilibrium?
a. Neutral
b. Stable
c. Unstable
____ 28. Based on stability concepts, you would expect a very broad tree to have
a. exceptionally strong roots.
b. very deep roots.
c. a very broad root system.
____ 29. You push a table tennis ball beneath the surface of water in a glass of water. The center of gravity
of the glass of water
a. rises.
b. falls.
c. neither rises nor falls.
____ 30. Torque is defined as _____.
a. mass times velocity
b. force times lever arm
c. momentum times radius
d. force times time
e. mass times acceleration
____ 31. Suppose you try loosening a nut with a wrench, and the nut doesn't give at all. You increase your
chance of success if you _____.
a. have a friend help you pull on the wrench
b. be sure to exert force perpendicular to the lever arm
c. exert a larger force
d. extend the lever arm
e. all of the above
____ 32. If a football is kicked so the force on the ball is through its center of gravity, the ball will _____.
a. tumble end over end in the air
b. not even get into the air
c. spin about its axis in the air
d. move without any tumbling or spinning
e. deflate
____ 33. The resistance an object has to changes in its rotational state of motion is called rotational _____.
a. inertia
b. momentum
c. torque
d. acceleration
e. velocity
____ 34. Which has more rotational inertia, a bicycle wheel or a solid disk of the same mass and diameter?
a. The wheel.
b. The disk.
c. They both have the same rotational inertia.
____ 35. Which has more rotational inertia, a girl running with her legs bent or the same girl running with
her legs straight?
a. With straight legs.
b. With bent legs.
c. Both have the same rotational inertia.
____ 36. When a gymnast moves from an extended position to a tucked position, she _____.
a. increases her rotational inertia
b. decreases her rotational inertia
c. neither A nor B
____ 37. Angular momentum is defined as _____.
a. momentum times rotational velocity
b. mass times velocity
c. rotational inertia times linear velocity
d. none of the above
____ 38. An object will maintain its angular momentum unless acted on by an unbalanced force.
a. Always true
b. Sometimes true
c. Always false
____ 39. When an ice skater pulls in his hands to turn faster _____.
a. angular momentum must be conserved
b. his moment of inertia changes
c. his rotational speed changes
d. all of the above
____ 40. If the planet Jupiter underwent gravitational collapse, its rate of rotation about its axis would
_____.
a. decrease
b. increase
c. stay the same
d. More information needed.
____ 41. Two people sit on a balanced seesaw. When one person leans toward the center of the seesaw,
that person's end of the seesaw will _____.
a. fall
b. rise
c. stay at the same level
____ 42. To turn a stubborn screw, it is best to use a screwdriver that has a _____.
a. yellow color
b. wide handle
c. long handle
d. none of the above
____ 43. Suppose a carnival Ferris wheel has seats that are located halfway between the center and the
outside rim. Compared to the ordinary Ferris wheel, where the seats are on the outside rim, your
rotational speed on this Ferris wheel would be _____.
a. greater
b. the same
c. smaller
____ 44. At the health spa, Felix Flex finds that pulleys on the exercise machines are not circular, but are
cams—oval-shaped pulleys. At different orientations, the cams provide different _____.
a. lengths of lever arms
b. forces required to produce a given torque
c. both A and B
d. none of the above
____ 45. A common thread spool rests on a flat table. You gently pull in a horizontal direction on a short
piece of thread wrapped around the spool. The spool will roll toward you _____.
a. whether the string is wound over or under the spool
b. only if the string is wound under the bottom of the spool spindle
c. only if the string is wound over the top of the spool spindle
____ 46. A meter stick is balanced at the 50.0-cm mark. You tie a 10.0-N weight at the 15.0-cm mark.
Where should a 30.0-N weight be placed so the meter stick will again be balanced?
a. 10.0-cm mark
b. 15.0-cm mark
c. 61.7-cm mark
d. 25.0-cm mark
e. 30.0-cm mark
____ 47. Newton had the insight to see that the _____.
a. moon is moving
b. moon orbits Earth
c. force on the moon has the same nature as the force on an apple
d. moon always keeps one side toward Earth
e. none of the above
____ 48. Newton reasoned that the gravitational attraction between Earth and the moon must be _____.
a. reduced by distance
b. independent of distance
c. directly proportional to distance
d. the same at all distances
e. all of the above
____ 49. A very massive object A and a less massive object B move toward each other under the influence
of mutual gravitation. Which force, if either, is greater?
a. The force on B
b. The force on A
c. Both forces are the same.
____ 50. Two objects move toward each other because of gravitational attraction. As the objects get closer
and closer, the force between them _____.
a. remains constant
b. decreases
c. increases
____ 51. Gravitational forces are the weakest forces found in nature. Because of this _____.
a. the gravitational effect between a pencil and Earth cannot be seen
b. there is no gravitational force between two 1-kg masses
c. gravitational forces that are easily observed involve one or more large masses
d. there is no movement between two 1-kg masses located near each other in space
e. gravitational effects occur only when a large mass is involved
____ 52. By noticing that Uranus's orbit is perturbed and by using the law of gravitation, two astronomers
independently discovered _____.
a. Neptune
b. exceptions to the law of gravitation
c. the law of gravitation fails at large distances
d. Uranus has several moons
____ 53. The force of gravity on you is greatest when you are standing _____.
a. far above Earth's surface
b. just above Earth's surface
c. on Earth's surface
____ 54. A lunar month is about 28 days. If the moon were closer to Earth than it is now, the lunar month
would be _____.
a. more than 28 days
b. unchanged at 28 days
c. less than 28 days
____ 55. A supplier wants to make a profit by buying metal by weight at one altitude and selling it at the
same price per pound at another altitude. The supplier should _____.
a. buy at a low altitude and sell at a high altitude
b. disregard altitude because it has a negligible effect
c. buy at a high altitude and sell at a low altitude
____ 56. A planet has half the mass of the Earth and half the radius. Compared to its weight on Earth, an
apple on this planet would weigh _____.
a. twice as much
b. one-fourth as much
c. half as much
d. the same
e. zero
____ 57. Consider the gravitational force between Earth and a meteor in outer space. If the meteor moves
so its distance from the Earth's center doubles, the gravitational force on the meteor will be
_____.
a. one quarter
b. half
c. double
d. quadruple
____ 58.
____ 59.
____ 60.
____ 61.
____ 62.
____ 63.
____ 64.
____ 65.
e. eight times greater
Which is greater, the gravitational force between Earth and the moon, or the force between Earth
and the sun?
a. Earth–moon
b. equal
c. Earth–sun
Jupiter has more than 300 times the mass of Earth. Yet on Jupiter's surface an object weighs only
about 3 times as much as it would on Earth. The explanation to this involves Jupiter's _____.
a. high density
b. greater distance from the sun
c. large radius
If you stood atop a ladder on Earth that was as tall as Earth's radius (so you were twice as far
from Earth's center) your weight atop the ladder would be _____.
a. one-eighth its normal value
b. one-quarter its normal value
c. half its normal value
d. none of the above
Why did Newton think there was a force acting on the moon?
a. Because the moon always keeps one side toward Earth
b. Because the moon moves in a curved path
c. Because there is no air on the moon
d. Because the moon is moving
e. all of the above
Since Earth is attracted to the sun, why doesn't it fall into the sun?
a. Because it has too much mass to move toward the sun
b. Because it has sufficient tangential velocity
c. Because there is an equal force holding it away from the sun
d. Because it has too much inertia to move toward the sun
e. all of the above
A 560-N woman stands on top of a very tall ladder so she is one Earth radius above Earth's
surface. How much does she weigh?
a. zero
b. 140 N
c. 280 N
d. 560 N
e. none of the above
Suppose the gravitational force between two masses is 70 N. If the magnitude of one of the
masses halves, what is the force between the masses?
a. 280 N
b. 140 N
c. 70 N
d. 35 N
e. 18 N
Suppose the gravitational force between two spheres is 70 N. If the distance between the spheres
is halved, what is the force between the masses?
a. 17.5 N
b. 35 N
c. 70 N
d. 140 N
e. 280 N
____ 66. Suppose the gravitational force between two spheres is 30 N. If the magnitude of each mass
doubles, what is the force between the masses?
a. 8 N
b. 15 N
c. 30 N
d. 60 N
e. 120 N
____ 67. If the mass of Earth increased, with no change in radius, your weight would _____.
a. increase also
b. stay the same
c. decrease
____ 68. If the radius of Earth decreased, with no change in mass, your weight would _____.
a. decrease
b. increase
c. not change
____ 69. According to Newton's laws, a rock and a pebble will fall with the same acceleration in a
gravitational field because the gravitational force on each is _____.
a. the same
b. different, though the ratio of the force to the mass of each is the same
c. none of the above
____ 70. The value of the acceleration due to gravity, g, _____.
a. depends on the universal gravitational constant, G
b. depends on the mass of Earth
c. is different on different planets
d. depends on the radius of Earth
e. all of the above
____ 71. We can tell if a gravitational force exists in a region of space if _____.
a. we disturb a pendulum and it starts swinging
b. we let go of a ball and it starts to move
c. a force exists on a mass placed there
d. we can weigh ourselves
e. all of the above
____ 72. Gravitational field lines show the _____.
a. direction of the field at each point
b. direction of the force on any mass
c. direction a mass would be accelerated
d. strength of the field
e. all of the above
____ 73. Compared to the gravitational field on the surface of Earth, the gravitational field well below
Earth's surface is _____.
a. larger
b. smaller
c. the same
____ 74. The gravitational field strength at the center of Earth is _____.
____ 75.
____ 76.
____ 77.
____ 78.
____ 79.
____ 80.
____ 81.
____ 82.
a. the same as on the surface
b. smaller than on the surface but still larger than zero
c. zero
d. large
If you were to weigh yourself in an elevator that is accelerating upward, compared to your
ordinary weight you would weigh _____.
a. more
b. less, but more than zero
c. the same
d. zero
If you were to weigh yourself in an elevator that is in free fall, compared to your ordinary weight,
you would weigh _____.
a. more
b. the same
c. less, but more than zero
d. zero
If you drop a stone into a hole drilled all the way to the other side of Earth, the stone will _____.
a. speed up until it gets to the center of Earth
b. slow down until it reaches the center of Earth
c. speed up until it reaches the other side of Earth
d. stop at the center of Earth
Ocean tides occur mainly because _____.
a. of the gravitational pull of the sun on Earth
b. water normally runs to the side of Earth away from the sun
c. of different gravitational pulls of the moon on opposite sides of Earth
d. as Earth rotates it leaves the ocean water somewhat behind it
e. none of the above
The effect of the sun's pull on Earth's oceans is much less visible than that of the moon's pull
because _____.
a. Earth is spinning so fast
b. the sun is so far away
c. Earth is orbiting so fast
d. the sun is radiating a lot of energy
e. none of the above
A lunar eclipse happens when _____.
a. the moon is between Earth and the sun
b. the sun is between Earth and the moon
c. Earth is between the moon and the sun
A solar eclipse happens when _____.
a. the moon is between Earth and the sun
b. Earth is between the moon and the sun
c. the sun is between Earth and the moon
Earth tides in which the solid surface of Earth rises and falls are caused by _____.
a. many volcanic eruptions
b. different forces between the moon and opposite parts of Earth
c. the alignment of the sun and the moon
d. the motion of water caused by ocean tides
e. none of the above—the solid surface of Earth cannot have tides.
____ 83. Suppose the moon had twice its present mass and still orbited Earth at the same distance. In that
case _____.
a. the ocean tide facing the moon would rise, and the other tide would lower
b. the ocean tides would be the same as they are now
c. both ocean tides would be smaller
d. the ocean tide facing the moon would lower, and the other tide would rise
e. both ocean tides would be higher
____ 84. Suppose the moon were covered with water and orbited Earth as it now does. In that case the
moon would have _____.
a. four tidal bulges
b. no tidal bulges
c. two tidal bulges
d. one tidal bulge
e. three tidal bulges
____ 85. There would still be two ocean tides per 24 hours if _____.
a. the sun's influence on the tides were negligible
b. Earth and moon had equal masses
c. the moon had more mass than Earth
d. any of the above
e. none of the above
____ 86. There are two main processes going on in the sun that keep the sun in existence. These processes
are gravitation and _____.
a. nuclear fusion
b. electrostatic repulsion
c. heat absorption
____ 87. A black hole is an object that _____.
a. alters the space around it
b. has an enormous density
c. has an enormous gravitational field near it
d. has an escape speed greater than the speed of light
e. all of the above
____ 88. If the sun were to collapse to form a black hole (quite unlikely), Earth would _____.
a. immediately disappear
b. spiral into the black hole
c. orbit the black hole just as it orbits the sun now
d. leave the solar system in the direction of its tangential velocity
e. be drawn into the black hole
____ 89. Which produces a greater tidal effect in your body, the moon or a 1-kg melon that you hold above
your head?
a. Not enough information given to make a reasonable estimate
b. The moon
c. The melon
____ 90. Which of these three produces the greatest tidal effect on you right now?
a. Earth
b. The moon
c. The sun
____ 91. A man who weighs 600 N at Earth's surface stands on top of a very tall ladder so he is one Earth
radius above Earth's surface. How much does he weigh?
a. zero
b.
c.
d.
e.
150 N
300 N
600 N
none of the above
____ 92. If Earth had twice its present mass, but the same radius, what would be the value of g?
a. 0 m/s2
b. 4.9 m/s2
c. 9.8 m/s2
d. 19.6 m/s2
e. 39.2 m/s2
____ 93. If the radius of Earth were one half what it is now, and the mass were the same, what would be
the value of g?
a. 0 m/s2
b. 4.9 m/s2
c. 9.8 m/s2
d. 19.6 m/s2
e. 39.2 m/s2
____ 94. The orbital speed for a satellite orbiting very close to Earth's surface is _____.
a. 1600 m/s
b. 4900 m/s
c. 8000 m/s
d. 16,000 m/s
e. 80,000 m/s
____ 95. The reason satellites orbit Earth at least 150 km above the surface is to _____.
a. be above Earth's gravity
b. make sure they are higher than the highest mountains
c. be above Earth's atmosphere
d. keep them out of the way of commercial airliners.
e. all of the above
____ 96. The speed of a satellite in a circular orbit is _____.
a. constant
b. not constant
c. constantly increasing
____ 97. The speed of a satellite in an elliptical orbit is _____.
a. independent of the height of the satellite
b. not constant
c. constant
____ 98. A period of a satellite is defined as _____.
a. the time for a satellite to cross the United States
b. 1 second
c. the time for a satellite to make one complete revolution around Earth
d. 90 seconds
e. 24 hours
____ 99. The higher a satellite is, the _____.
a. less its speed is
____ 100.
____ 101.
____ 102.
____ 103.
____ 104.
____ 105.
____ 106.
____ 107.
____ 108.
b. greater its speed is
c. longer its period is
d. both A and C
e. both B and C
A circle is a special case of _____.
a. a hyperbola
b. a parabola
c. an ellipse
d. a focus
The fastest moving planet in a solar system is _____.
a. the most massive planet
b. any planet (they all move at the same speed)
c. the smallest planet
d. the planet nearest the sun
Pluto takes a longer time to travel around the sun than Earth takes because Pluto _____.
a. has farther to go
b. goes slower
c. both A and B
d. none of the above
An object is placed exactly halfway between Earth and the moon. The object will fall toward
_____.
a. the moon
b. Earth
c. neither Earth nor the moon
An object dropped from rest almost infinitely far from Earth falls to Earth because of Earth's
gravitational field, and strikes the surface with a speed of about _____.
a. 8 km/s
b. 9.8 m/s
c. 11 km/s
d. none of the above
Compared to the period of a satellite in orbit close to Earth, the period of a satellite in orbit far
from Earth is _____.
a. the same
b. longer
c. shorter
d. Not enough information
The force of gravity does work on a satellite when it is in _____.
a. circular orbit
b. elliptical orbit
c. both A and B
d. neither A nor B
What remains constant for a satellite in an elliptical orbit?
a. Its speed
b. Its potential energy
c. Its total energy
d. Its kinetic energy
e. Its distance from the planet
Escape speed from the surface of Earth is about _____.
a. 8 km/s
____ 109.
____ 110.
____ 111.
____ 112.
____ 113.
____ 114.
____ 115.
____ 116.
____ 117.
b. 9.8 km/s
c. 11.2 km/s
d. 16 km/s
e. It is impossible to completely escape from Earth.
The curvature of Earth is such that for every 8000 m tangent to the surface, the surface drops
about _____.
a. 0 m
b. 2.5 m
c. 5 m
d. 10 m
e. 20 m
Minimal orbital speed about Earth is approximately 8 km/s. Minimal orbital speed about the
moon would be _____.
a. less than 8 km/s
b. about 8 km/s
c. more than 8 km/s
When we move around through space just a little bit, we are moving _____.
a. through time only
b. only through space
c. mostly through time and only a little bit through space
d. mostly through space and only a little bit through time
e. none of the above
Light is different from objects with mass in that no matter how fast the source of light is moving,
light always _____.
a. has the same color
b. has the same period
c. has the same speed
d. travels in the same direction
e. all of the above
Suppose we observe light bouncing back and forth between two vertical clock mirrors in a
spaceship that is whizzing past us at a very high speed. Compared to what the person in the
spaceship sees, we see the spaceship clock as running _____.
a. just the same
b. fast
c. slow
If you are moving in a high-speed spaceship relative to the Earth, you would _____.
a. notice your pulse slowing down
b. be able to do much more in an hour than ever before
c. notice all your clocks have slowed down
d. all of the above
e. none of the above
Clocks on a spaceship moving very fast appear to run slow when viewed from _____.
a. the spaceship
c. both A and B
b. Earth
d. neither A nor B
When you approach a light source that in turn is moving towards you, your speed relative to the
emitted light waves _____.
a. decreases
b. increases
c. stays the same
We are actually looking into the past when we look at _____.
a. starlight
c. both A and B
b. our physics book
d. none of the above
____ 118. In some reference frame in the universe, you, right now, are traveling at a speed close to the
speed of light.
a. False
b. True
____ 119. Compared to time kept on Earth, there is a physical slowing of time when you travel at _____.
a. everyday low speeds.
c. both A and B
b. relativistic speeds.
d. none of the above
____ 120. A friend is riding on the back of a truck that is going away from you at 25 km/hr. After the truck
passes, your friend throws a ball toward you at 55 km/h relative to her. How fast is the ball going
relative to you?
a. 25 km/h
b. 30 km/h
c. 55 km/h
d. 80 km/h
e. 105 km/h
____ 121. To a person who is inside a spaceship moving close to the speed of light, a meter stick held
horizontally inside the ship looks
a. squashed in the direction of motion.
b. taller.
c. wider in the direction of motion.
d. shorter.
e. just the same as always.
____ 122. To calculate how much rest energy an object contains, you multiply
a. its mass times its velocity.
b. the force on it times the length of time the force acts.
c. its mass times its acceleration.
d. its mass times the speed of light squared.
e. one half its mass times its velocity squared.
____ 123. Objects accelerated to relativistic speeds appear to
a. grow bigger.
b. gain momentum.
c. live a shorter time.
d. all of the above
e. none of the above
____ 124. A woman standing on the ground sees a rocket ship move past her at 95% the speed of light.
Compared to the rocket at rest, the woman sees the rocket's length as
a. longer.
b. the same.
c. shorter.
____ 125. When an object is pushed to relativistic speeds, its momentum is measured to be
a. smaller than mv.
b. greater than mv.
c. the same as mv.
____ 126. According to the well-known equation "energy equals mass times the speed of light squared,"
a. mass and energy travel at the speed of light squared.
b. mass and energy travel at twice the speed of light.
c. energy is actually mass traveling at the speed of light squared.
d. mass and energy are related.
e. none of the above
____ 127. If you were to travel at speeds close to the speed of light, you would notice that your
a. shape changes.
b. mass increases.
c. pulse decreases.
d. all of the above
e. none of the above
____ 128. To outside observers, objects traveling at relativistic speeds look
a. larger.
b. smaller.
c. the same size.
____ 129. A spaceship whizzes past a space station at close to the speed of light. An observer on the station
measures the length of the spaceship as less than when the ship is at rest, and an observer on the
spaceship measures the length of the space station as
a. the same as when the spaceship isn't moving.
b. greater than when the spaceship isn't moving.
c. less than when the spaceship isn't moving.
____ 130. There is an upper limit on the speed of a particle. This means there is also an upper limit on its
a. kinetic energy.
b. momentum.
c. both A and B
d. none of the above
____ 131. A 10-meter-long spear is thrown at a relativistic speed through a 10-meter-long pipe (both
measured when at rest.) When the spear passes through the pipe,
a. the pipe shrinks so the spear extends at both ends.
b. both shrink equally so the pipe barely covers the spear.
c. the spear shrinks so the pipe completely covers it.
d. any of the above, depending on the motion of the observer
e. none of the above
____ 132. The correspondence principle says that
a. any new theory must correctly predict observations.
b. the new theory is correct.
c. the old theory is correct.
d. any new theory must agree with the old correct theory.
____ 133. If Einstein's equations of special relativity are valid, they must
a. reduce to Newton's equations when the speed is small.
b. give correct answers for speeds much less than the speed of light.
c. agree with the correct results of Newton's equations.
d. both A and C
e. A, B, and C
____ 134. There are slightly more than 100 known atoms that combine to form all living and nonliving
matter that we know about. These atoms are called _____.
a. isotopes
b. nucleons
c. molecules
d. ions
e. elements
____ 135. What is the most abundant element in the known universe?
a. Nitrogen
b. Oxygen
c. Hydrogen
d. Carbon
e. Water
____ 136. Nearly all the elements heavier than hydrogen that occur today were created _____.
a. in the deep interior of stars
b. at the same time the universe was created
c. in the center of Earth
d. by collisions in deep space
e. at the same time the solar system was created
____ 137. Atoms are _____.
a. smaller than the wavelength of visible light
b. small, but you can see them with an optical microscope
c. so small that we can only postulate their existence
d. seen only through a microscope looking through another microscope
e. so small that we can never see them, even with an electron microscope
____ 138. Assuming all the atoms exhaled by Julius Caesar in his last dying breath are still in the
atmosphere, then it is likely that we breathe one of those atoms _____.
a. every month
b. every 10 years
c. with each single breath
d. every day
____ 139. Nuclei of atoms that make up a newborn baby were made in _____.
a. the mother's womb
b. the food the mother ate before giving birth
c. Earth
d. ancient stars
e. none of the above
____ 140. If we doubled the magnifying power of the most powerful optical microscope in the world, we
would _____.
a. still not be able to see an atom
b. be able to photograph individual atoms, even though we couldn't see them
c. be able to see individual atoms
____ 141. Which of the following atoms is the lightest?
a. Lead
b. Iron
c. Hydrogen
d. Uranium
e. All have the same mass
____ 142. Which of the following statements is true?
a. There are millions of different kinds of atoms that form all substances.
b. An atom is the smallest particle known to exist.
c. There are slightly over 100 different kinds of atoms that combine to form all substances.
d. Atoms are so small that there is no way we can photograph them.
e. None of the above statements is true.
____ 143. What makes an element distinct?
a. The number of neutrons
b. The number of electrons
c. The number of protons
d. The total mass of all the particles
e. none of the above
____ 144. What normally determines whether a substance is a liquid, solid, gas, or plasma?
a. The atomic mass of the atoms involved
b. The density of the substance
c. The atomic number of the atoms involved
d. The temperature of the substance
e. none of the above
____ 145. Compounds are made of molecules.
a. Always false
b. Always true
c. Sometimes true
____ 146. The reason nuclei don't pack together more closely is _____.
a. because of large electromagnetic repulsion forces
b. that it is not allowed according to an exclusion principle
c. that there isn't enough room between atoms
d. because of large nuclear repulsion forces
e. because outer electrons form a hard, impenetrable shell
____ 147. Which of the following is NOT a compound?
a. Water
b. Air
c. Ammonia
d. Salt
e. All are compounds.
____ 148. In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal
number of _____.
a. neutrons
b. electrons
c. pions
d. all of the above
e. none of the above
____ 149. Which is the smallest particle of those listed below?
a. A proton
b. A molecule
c. An atom
d. A nucleus
____ 150. The reason a granite block is mostly empty space is because the atoms in the granite are _____.
a. held together by electrical forces
b. in perpetual motion
c. mostly empty space themselves
d. not as close together as they could be
e. invisible
____ 151. Two isotopes of an element have different _____.
a. numbers of protons
b. numbers of neutrons
c. numbers of electrons
d. numbers of ions
____ 152. Sometimes an atom has more or fewer electrons than it does protons. Such an atom is called
_____.
a. an ion
b. a molecule
c. a compound
d. an isotope
e. an element
____ 153. The charge on an atom that has one less electron than protons is _____.
a. neutral
b. negative
c. positive
____ 154. Elements that are side by side in the periodic table have one more or one less _____.
a. nucleon
b. electron shell
c. proton
d. isotope
e. ion
____ 155. Most of the matter of the universe is in which phase?
a. Solid
b. Gas
c. Liquid
d. Plasma
e. Superconducting
____ 156. Plasmas _____.
a. are like the matter in a star
b. exist at high temperatures
c. are a gas of free electrons and ions
d. all of the above
e. none of the above
____ 157. Keep heating a gas and you'll have a _____.
a. liquid
b. plasma
c. both A and B
d. neither A nor B
____ 158. How many electrons can the innermost shell of an atom have?
a. 0
b. 2
c. 4
d. 6
e. 8
____ 159. If two protons are removed from an oxygen nucleus, the result is _____.
a. carbon
b. neon
c. nitrogen
d. helium
e. none of the above
____ 160. If one neutron is added to a hydrogen nucleus, the result is _____.
a. helium
b. deuterium
c. boron
d. beryllium
e. lithium
____ 161. Crystals are _____.
a. a specific kind of mineral
b. an orderly arrangement of atoms in a substance
c. a type of glass
d. a random arrangement of atoms in a substance
e. an orderly arrangement of minerals
____ 162. Density is defined as _____.
a. length divided by volume
b. length divided by time
c. mass divided by volume
d. mass times acceleration
e. none of the above
____ 163. Which has more density, a bushel of apples or 10 bushels of apples?
a. 1 bushel
b. 10 bushels
c. Both have the same density.
____ 164. Which has more density, a loaf of bread just after it comes out of the oven or the same loaf that
has been squeezed into a small volume?
a. The squeezed loaf
b. The fresh loaf
c. They both have the same density.
____ 165. Which has the greater density, a lake full of water or a cup full of lake water?
a. The cup
b. Both have the same density.
c. The lake
____ 166. Compared to the density of a kilogram of feathers, the density of a kilogram of lead is _____.
a. less
b. more
c. the same
____ 167. If the mass of an object were to double while its volume remained the same, its density would
_____.
a. double
b. halve
c. stay the same
____ 168. If the volume of an object were to double while its mass stayed the same, its density would
_____.
a. halve
b. double
c. stay the same
____ 169. When used horizontally in construction, an I-beam is nearly as strong as a solid bar because
_____.
a. tension and compression are predominantly in the top and bottom parts
b. of the effects of scaling
c. it is perpendicular to gravity
d. the I-beam weighs less
____ 170. The existence of crystals in many solids was not discovered until _____ became a tool of research
in the twentieth century.
a. Hooke’s law
b. scaling
c. x-rays
d. gamma rays
____ 171. Less force is required to poke through an eggshell from the _____.
a. outside in
b. Force is the same in both directions.
c. inside out
____ 172. Which geometrical shape has the least surface area for a given volume?
a. pyramid
b. cube
c. cylinder
d. sphere
e. none of the above
____ 173. If all dimensions of a house were to double, its floor area would go up by a factor of _____.
a. 2
b. 3
c. 4
d. 8
e. 16
____ 174. If an ant were scaled up to the size of an elephant, the ant would be _____.
a. much stronger than the elephant
b. weaker than the elephant, but able to run around
c. of the same strength as the elephant
d. too weak to even lift itself off the ground
____ 175. The main reason an elephant has big ears is so it can _____.
a. cool off by fanning itself
b. live longer
c. hear better
d. cool off by radiating more heat
e. none of the above
____ 176. Which has more skin per body weight, an elephant or a mouse?
a. The elephant
b. The mouse
c. Neither—they both have the same amount of skin per body weight.
____ 177. Compared to a 50-kg sunbather, a 100-kg sunbather requires _____.
a. the same amount of suntan lotion
b. less than twice as much suntan lotion
c. more than twice as much suntan lotion
____ 178. Bob is making taffy apples. If he buys 100 kg of small apples rather than 100 kg of large apples,
he will need _____.
a. the same amount of taffy
b. more taffy
c. less taffy
____ 179. An elephant eats less for its size than smaller animals because _____.
a. its surface area is large compared to its volume
b. its surface area is small compared to its volume
c. its ears are bigger
d. it is taller than other animals
e. it weighs more than smaller animals
____ 180. If an elephant grew to twice its height, the area of its ears would change by a factor of _____.
a. 2
b. 4
c. 6
d. 8
e. none of the above
____ 181. An elephant that grows to twice its normal height will increase its weight by a factor of about
_____.
a. 2
b. 4
c. 6
d. 8
e. none of the above
____ 182. Suppose all sizes of potatoes are selling at the same price per kilogram. For a given amount of
money, you will have a greater mass of potatoes after they are peeled, if you buy _____.
a. small potatoes
b. large potatoes
c. medium potatoes
d. a mixture of sizes
____ 183. If in making cupcakes you bake them as directed for a cake, you will find the cupcakes _____.
a. underbaked
b. overbaked
c. properly baked
____ 184. In cold weather, your hands will be warmer if you wear _____.
a. mittens
b. gloves
c. either A or B—there is no difference.
____ 185. If each dimension of a steel bridge is scaled up 10 times, its strength will increase by _____.
a. 100, but its weight by 1000
b. 1000, and its weight by 100
c. 10, and its weight by 10 also
d. none of the above
____ 186. What is the density of a rock that has a mass of 350 g and a volume of 250 cubic centimeters?
a. 0.7 g/cubic cm
b. 1.4 g/cubic cm
c. 600 g/cubic cm
d. 3,500 g/cubic cm
e. 87,500 g/cubic cm
____ 187. What is the weight density of a tub of water that weighs 2940 N and occupies a volume of 4 cubic
meters?
a. 184 N/cubic m
b. 368 N/cubic m
c. 735 N/cubic m
d. 2,940 N/cubic m
e. 11,760 N/cubic m
____ 188. When a 4-N weight is hung from a spring, the spring stretches 0.03 m. How much does the spring
stretch when an 8-N weight is hung from it?
a. 0.02 m
b. 0.03 m
c. 0.12 m
d. 0.06 m
e. 0.24 m
____ 189. A 4-kg load stretches an elastic belt 0.02 m. How much will a 6-kg load stretch the belt?
a. 0.12 m
b. 0.02 m
c. 0.03 m
d. 0.01 m
e. 0.08 m
____ 190. If all dimensions of a house were doubled, its volume would go up by a factor of _____.
a. 2
b. 3
c. 4
d. 6
e. 8
____ 191. Pressure in a liquid depends on the _____.
a. depth of the measuring point
b. mass of the liquid
c. volume of the liquid
d. density of the liquid
e. both A and D
____ 192. The pressure at the bottom of a jug filled with water does NOT depend on the _____.
a. surface area of the water
b. density of water
c. depth of the liquid
d. acceleration due to gravity
e. none of the above
____ 193. Archimedes' principle says that an object is buoyed up by a force that is equal to the _____.
a. weight of the fluid displaced
b. mass of the fluid displaced
c. volume of the fluid displaced
____ 194.
____ 195.
____ 196.
____ 197.
d. mass of the object
e. none of the above
The buoyant force on an object is least when the object is _____.
a. submerged near the bottom
b. partly submerged
c. submerged near the surface
d. none of the above
The reason objects immersed in a fluid experience an upward buoyant force is because fluid
pressure on the bottom of the object is greater than fluid pressure on the top of the object.
a. True
b. False
The reason a life jacket helps you float is that _____.
a. the jacket repels water
b. the jacket makes you weigh less
c. the jacket has the same density as an average human
d. you and the jacket together have density less than your density alone
Lobsters live on the bottom of the ocean. The density of a lobster is _____.
a. equal to the density of seawater
b. greater than the density of seawater
c. less than the density of seawater
____ 198. The density of a submerged submarine is about the same as the density of _____.
a. iron
b. a crab
c. a floating submarine
d. water
e. none of the above
____ 199. If an object has a density greater than the density of water, it will _____.
a. sink
b. neither float nor sink, but stay anywhere it is put
c. float
____ 200. If an object has a density equal to the density of water, it will _____.
a. neither float nor sink, but stay anywhere it is put
b. sink
c. float
____ 201. The reason an iron ship doesn't sink is that _____.
a. iron is less dense than water
b. air inside decreases it's weight
c. the iron displaces more water than it would if it were in a solid block
d. an iron ship will always sink
____ 202. When first put in water, a plastic toy boat will sink until _____.
a. it displaces a volume of water equal to its own volume
b. the water density equals the density of the boat
c. it displaces a weight of water equal to its own weight
d. the buoyant force equals the volume of the boat
e. the buoyant force equals the density of the boat
____ 203. Compared to an empty ship, the same ship loaded with plastic foam will float _____.
a. at the same level in the water
b. lower in the water
____ 204.
____ 205.
____ 206.
____ 207.
c. higher in the water
A block of balsa wood floats on water while a block of lead the same size lies submerged in the
water. The buoyant force is _____.
a. greater on the lead
b. greater on the wood
c. the same for both
A kilogram of lead and a kilogram of aluminum are submerged in water. The buoyant
force is _____.
a. greater on the aluminum
b. greater on the lead
c. the same for both
When a boat sails from fresh water to salt water, the boat will float _____.
a. at the same level
b. higher in the salt water
c. lower in the salt water
If the part of an iceberg that extends above the water were removed, the _____.
a. density of the iceberg would change
b. iceberg would sink
c. iceberg would rise
d. pressure on the bottom of the iceberg would increase
e. none of the above
____ 208. If a weighted, air-filled balloon sinks in a lake, it will _____.
a. be buoyed up with constant force while sinking
b. probably sink to the bottom and probably rise later
c. sink until it reaches equilibrium and then remain at constant depth
d. always sink to the bottom
e. none of the above
____ 209. When an ice cube in a glass of water melts, the water level _____.
a. remains the same
b. rises
c. falls
____ 210. A floating ice cube contains a small piece of iron. After the ice cube melts, the water level will
_____.
a. fall
b. rise
c. remain unchanged
____ 211. An ice cube floating in a glass of water contains many air bubbles. When the ice melts, the water
level will _____.
a. remain unchanged
b. rise
c. fall
____ 212. There is a legend of a Dutch boy who bravely held back the Atlantic Ocean by plugging a leak
near the top of a dike with his finger until help arrived. Which of the following is most likely?
a. The force on his finger would have been huge, but the pressure very small.
b. This is impossible because of the large size of the Atlantic Ocean.
c. The force on his finger would have been less than 1 N.
d. Both the force and pressure on his finger would have been very large.
e. none of the above
____ 213. When you float in salt water compared to floating in fresh water, the buoyant force that supports
you is _____.
a. the same
b. greater
c. less
____ 214. Pascal's principle says that changes in pressure at any point in an enclosed fluid _____.
a. remain only at the point
b. are transmitted to all points in the fluid
c. quickly diminish from point to point in the fluid
d. are transmitted only to points below it
e. are transmitted only to points close to it
____ 215. The principle reason a hydraulic press works is that it is an exception to energy conservation.
a. Sometimes true
b. Always true
c. Always false
____ 216. A hydraulic arrangement consists of a water-filled U-tube that is wider on one end than on the
other. Pistons are fitted in both ends. To multiply an input force, the input end should be the one
having the _____.
a. larger-diameter piston
b. smaller-diameter piston
c. It doesn't matter what relative size the piston is.
____ 217. In a hydraulic device, the output piston has 100 times the cross-section area as the input piston.
This means the device will multiply force _____.
a. 1000 times
b. 100 times
c. 10 times
d. none of the above
____ 218. A hydraulic press multiplies a force by 100. This multiplication is done at the expense of _____.
a. the distance through which the force acts
b. the time over which the force acts, which is extended by a factor of 100
c. the mechanism providing the force
d. energy, which decreases by a factor of 100
e. none of the above
____ 219. In a hydraulic press operation, it is impossible for the _____.
a. force output to exceed the force input
b. output displacement to exceed the input displacement
c. energy output to exceed the energy input
d. none of the above
____ 220. An industrial container holds 100 N of water. The area of the inside bottom of the container is 2
square meters. What pressure does the water exert on the bottom of the container?
a. 0.02 N per square meter
b. 50 N per square meter
c. 100 N per square meter
d. 400 N per square meter
e. none of the above
____ 221. Suppose a stone weighs 8 N in the air, but in water it weighs only 5 N. What is the buoyant force
acting on the stone?
a. 3 N
b. 5 N
c. 8 N
d. 13 N
e. 16 N
____ 222. One liter of water weighs about 10 N. Suppose a 3-liter container is filled with 266 N of mercury
and then lowered into a container of water. Assuming the container is completely submerged,
what is the buoyant force acting on it?
a. 30 N
b. 266 N
c. 27 N
d. 89 N
e. 10 N
____ 223. The volume of water displaced by a floating 20,000-N boat _____.
a. is the volume of the boat
b. depends on the shape of the ship's hull
c. is 20,000 cubic meters
d. is the volume of 20,000 N of water
____ 224. Floating Freda, who can just barely float in fresh water, has a mass of 44 kg. Her volume is
therefore about _____.
a. 22 liters
b. 44 liters
c. 220 liters
d. none of the above
____ 225. A 40,000-N car is lifted on a hydraulic piston of area 1000 square centimeters. How much force
on a 10 square-centimeter piston is needed to lift the car?
a. 40,000 N
b. 10,000 N
c. 8,000 N
d. 4,000 N
e. 400 N
Problem
226. The tangential speed at the outer rim of a Ferris wheel is 10 m/s. What is the tangential speed of a
position half way from the center to the outer rim?
227. You sit at the outer rim of a Ferris wheel that rotates at 2 revolutions per minute (RPM). What
would your rotational speed be if you were instead clinging to a position halfway from the center
to the outer rim?
228. A vertical pole standing against a wall topples to the ground and the center of the pole has a speed
of 13 m/s as it hits. With what speed does the far end of the pole hit the ground?
229. Tapered rims on railroad-train wheels enable a train to round curves without any wheel skidding.
Consider a curve where the outer track is one part in 50 longer than the inner track. The wide part
of the rim should have a diameter wider than the narrow part by at least one part in
230. At the outer edge of a rotating space habitat, 130 m from its center, the rotational acceleration is
g. What is the rotational acceleration at a distance of 65 m from the center of the habitat?
231. A 40-kg boy sits on a seesaw 2.0 m from the fulcrum. What distance from the fulcrum should a
30-kg girl sit in order to balance the seesaw?
232. Consider a long uniform wooden plank of weight W resting on a table. The left end of the plank
can extend beyond the table without toppling as long as the CG of the plank rests on the table. If
the CG extends beyond the table's edge, then a weight placed on its right end can prevent
toppling. How much weight would prevent toppling if of the plank extended beyond the edge?
233. What would a person who weighs 610 N on Earth weigh on a planet that has the same mass as
Earth but half its radius?
234. Jupiter has a mass about 300 times that of Earth, and its radius is about 11 times that of Earth.
What would be the approximate weight of a 5-kg rock on the surface of Jupiter?
235. Satellites often orbit 640 km above Earth's surface (640 km = 10% of Earth's radius). What is
Earth's approximate gravitational field, g, in satellite territory?
236. What is Earth's gravitational field, g, 2 Earth-diameters from Earth's surface (5 r from Earth's
center)?
1
237. Suppose you're standing on the surface of a shrinking planet. If it shrinks to 4 its diameter (and its
mass remains the same), how many times as much would you weigh on the shrunken surface?
238. The tidal force of the moon on you right now is about 3.0
away, what would be the moon's tidal force on you?
10-13 N/kg. If the moon were
1
4
as far
239. The tidal force of Earth on you is about
N/kg. If Earth's mass were the same but its
diameter 6 times as great, what would be Earth's tidal force on you?
240. A woman 1.70 m tall lies along the axis of a space vehicle traveling at 0.95c. What is her height
as measured by a stationary observer?
241. How fast must a particle move if its momentum is to be 2.6 times its classical momentum?
242. What is the mass equivalent of 2.0 MJ?
243. The fractional change of mass to energy in a fission reactor is about 0.1%, or 1 part in a thousand.
If 1.0 kg of uranium undergoes fission, what amount of energy is released?
244. About how much pressure do the feet of a 6000-kg elephant exert on the ground? Assume each
foot has an area of 0.10 square meter.
245. What is the difference in water pressure between the top and bottom of a 100-m deep well?
246. What is the volume of a 70-kg person who can just barely float in fresh water?
247. The area of the bottom of a rectangular barge is 30.0 m2. When loaded with gravel the barge sinks
2.8 m in the water. What is the weight of the gravel and the barge?
248. A 4.0-kg toy boat that is 0.7 times the density of water floats in water. What mass of water is
displaced?
249. When a 3-kg stone is suspended in water, its apparent mass is 1.5 kg. What is the density of the
stone compared to the density of water?
250. The cross-sectional area of the output piston in a hydraulic device is 10 times the area of the input
piston. By how much can the device multiply the input force?