Phys 1000
Spring 2015
Name:_______________________________
Test 2
March 4, 2015
INSTRUCTIONS:
a) No books, notes, or other such materials are permitted.
b) NO CALCULATORS OR MOBILE PHONES ARE PERMITTED!!!
c) There is only one correct answer for each question. However, if you feel that more
than one answer is correct then you should choose the one you feel is most correct.
EACH QUESTION IS WORTH 5 POINTS
(There are 20 questions for a total of 100 points.)
g = 9.8 m/s/s = 32 ft/s/s
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1. A woman sits stationary with her feet up on a stool that is free to rotate.
(a) If she twists her body suddenly to the left, she and the chair will rotate continuously to
the right.
(b) She will not be able to cause continual motion of the stool rotation regardless of how she
moves her body.
(c) If she twists her body suddenly to the right, the chair will rotate continuously to the right.
(d) She will begin to rotate if she keeps her arms close to her body.
2. You throw a tennis racquet spinning into the air.
(a) The racquet always spins about a “special point”.
(b) The “special point” is determined by how you spin it.
(c) The racquet spins in a random way depending on how you throw it.
(d) It moves in an unpredictable way.
3. A 60 lb child and a 40 lb child can balance on a seesaw if
(a) The 40 lb child sits closer to the pivot point.
(b) The downward forces they exert on the seesaw are equal.
(c) The torques they exert on the seesaw are equal and opposite.
(d) The lever arms are equal.
4. Carrying a long pole helps a tightrope walker to maintain balance because
(a) It lowers the center-of-mass of the tightrope walker.
(b) Of the long lever arm.
(c) It decreases the torque on the tightrope walker.
(d) Of the large rotational inertia of the pole.
5. An ice skater standing on frictionless ice catches a large snowball thrown directly towards
her.
(a) The skater can catch the snowball and remain motionless.
(b) Momentum is not conserved in this “collision”.
(c) The skater and the snowball recoil with the speed of the snowball.
(d) The skater and the snowball recoil together with the original momentum of the snowball.
6. A revolving door will be most difficult to rotate if
(a) Most of the mass is concentrated near the center.
(b) Most of the mass is concentrated at the outer edge.
(c) The mass is distributed uniformly throughout the door.
(d) Most of the mass is concentrated along the top and bottom edges.
7. A gymnast does a somersault and then lands on the mat. When landing she instinctively
bends her knees a little bit to
(a) Minimize the force of impact.
(b) Maximize her momentum in stopping.
(c) Increase her velocity.
(d) Decrease her time in stopping.
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8. A bullet is fired from a rifle.
(a) The same momentum is given to the bullet and the rifle.
(b) The rifle receives a small amount of momentum as evidenced by the “kick”.
(c) The rifle is unaffected by the firing.
(d) The bullet has most of the momentum.
9. A bowling ball collides head on with a stationary golf ball. Immediately after colliding
(a) The balls move forward together at the same speed as the initially moving bowling ball.
(b) Momentum is not conserved in such a collision.
(c) The golf ball moves forward at nearly twice the speed of the bowling ball.
(d) The bowling ball stops and the golf ball moves forward at the initial speed of the bowling
ball.
10. A car weighing half as much as a truck travels at twice the speed of the truck.
(a) The car and truck will be equally difficult to stop.
(b) The car is easier to stop because it is lighter.
(c) The car is more difficult to stop because it is moving faster.
(d) The truck is more difficult to stop because it is heavier.
11. A stationary bicycle falls over while a fast moving one coasts quite well because
(a) The stationary bicycle has less rotational inertia.
(b) The spinning wheels have more force on them.
(c) There is no torque on the stationary bicycle.
(d) Gravity exerts a torque on the moving bicycle that is opposed by the reaction torque of
the bicycle.
12. You "follow through" when you hit a golf ball in order to
(a) Reduce the amount of force needed to hit the ball.
(b) Increase the time of contact with the ball.
(c) Hit the ball with maximum force.
(d) Increase the force of contact.
13. A spring scale is useful for measuring the weight of objects because
(a) The stretch of the spring does not depend on the force that is applied to it.
(b) It can support objects with weights greater than its own weight.
(c) The stretch of the spring is proportional to the force that the spring exerts.
(d) It has a dial to read the weight of the object.
14. Which of the following acts least like a spring?
(a) A tennis ball.
(b) A golf club.
(c) An apple.
(d) A plastic ruler.
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15. A baseball bat moving at 60 mi/hr hits an oncoming baseball "head on" and moving at 60
mi/hr towards the bat. The maximum speed at which the baseball can leave the bat (relative
to a stationary observer) is
(a) 60 mi/hr.
(b) 120 mi/hr.
(c) 180 mi/hr.
(d) 240 mi/hr.
16. You squeeze a tennis ball between your hands compressing it by 1 millimeter. To compress
the same ball by 2 millimeters
(a) Requires a greater momentum.
(b) Twice the force is required.
(c) Requires twice the torque.
(d) The same force is required.
17. A ball bounces because
(a) Gravitational PE is converted to KE.
(b) Elastic PE is converted to KE.
(c) KE is converted to thermal energy.
(d) Thermal energy is converted to elastic PE.
18. A baseball strikes a bat at the vibrational node near the big end of the bat.
(a) The handle of the bat rotates backward.
(b) The bat vibrates excessively.
(c) The entire bat moves backward without rotating.
(d) The bat does not vibrate.
19. You are standing on a bathroom scale inside an elevator at rest. The cable suddenly breaks
and you fall freely. (Don't worry, there is a large cushion to catch you!).
(a) The scale reads zero because you and the scale fall together.
(b) The scale will read less than your normal weight but not zero.
(c) The scale will read more than your normal weight.
(d) The scale still reads your normal weight because you and the scale fall together.
20. A female high school pitcher can throw a softball at about 65 mi/hr, while a major league
baseball pitcher can rarely throw a baseball faster than 100 mi/hr. This is because
(a) The energy required to throw increases proportional to the velocity.
(b) The major league pitcher has to throw with twice the force to get this velocity.
(c) The energy required is proportional to the square of the speed.
(d) Because the girl moves her arm in a complete circle before throwing the ball.
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