Name: ________________________ Class: ___________________ Date: __________
ID: A
Exam 2 -- PHYS 101
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1. A 10 kg object undergoes an acceleration of 2 m/s 2. What is the magnitude of the force acting on this object?
a. 5 N
c. 10 N
b. 20 N
d. 2 N
2. Two blocks are fastened to the ceiling of an elevator as in this figure. The elevator accelerates upward at an
acceleration of 5.0 m/s 2. What is the tension in the lower rope?
a. 98 N
c. 148 N
b. 50 N
d. 48 N
3. A block with mass 1.0 kg sits on the floor. A force of 5 N is required to move the block. What is the
coefficient of static friction?
a. 0.1
c. 0.05
b. 0.2
d. 0.5
4. A block of mass m rests on the floor of an elevator that is accelerating upward. What is the relationship
between the force due to gravity (mg) and the normal force (N) on the block?
a. N=mg
d. N=0
b. N>mg
e. depends on the speed of the elevator
c. N<mg
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Name: ________________________
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ID: A
5. The Earth’s mass is 5.98×1024 kg, and its radius is 6.38×106 m. The acceleration of gravity is 9.799 m/s 2.
What would the acceleration due to gravity at an altitude of 40,000 m? (G=6.67 ×10-11 Nm2/kg2)
a. 9.799 m/s2
c. 9.921
2
d. Not enough information given
b. 9.677 m/s
6. Gravitons are a theoretical particle or wave that are thought to do what?
a. transfer the force of gravity between 2
d. make scientists appear to be smarter than
objects
they really are
b. reflect light from one object to another
e. transfer heat between 2 objects
c. move mass from one body to another
7. Two bodies have masses 2×107 kg and 4×107 kg. They are separated by a distance of 100 m. What is the
magnitude of the gravitational force acting on less massive object? (G=6.67 ×10-11 Nm2/kg2)
a. 5 N
c. 500 N
b. 10,000 N
d. 20,000 N
8. The normal force on an object is always:
a. in the upward direction
d. opposite the direction of the object’s
motion
b. perpendicular to the surface on which the e. abnormally large
object sits
c. equal to the gravitational force
9. In this figure, the block has a mass of 10 kg and sits on an incline plane with an angle
θ=30°. The block is stationary. What is the minimum coefficient of static friction?
a. 0.2
c. 0.4
b. 0.6
d. 1.3
____ 10. The unit for work and energy is the Joule. This unit is made of what SI units?
a. N/m
c. kg m2/s2
2
2
b. m /s
d. kg m/s2
____ 11. A force of 10 N at an angle of 60° is applied to a wooden block. This force causes the block to move 1
meter. What is the work done by the force
a. 10 J
c. 9 J
b. 5 J
d. -10 J
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Name: ________________________
ID: A
____ 12. A 10 kg dog runs at 2 m/s. What speed must a 4 kg cat have in order to thave the same kinetic energy as the
dog?
a. 3 m/s
c. 0.8 m/s
b. 5 m/s
d. 6 m/s
____ 13. What is the height from which you must drop a ball (with mass of 5 kg) so that it will have a speed of 10 m/s
just before it hits the ground?
a. 2 m
c. 50 m
b. 5 m
d. 0.5 m
____ 14. In this figure, the bead has a mass of 0.100 kg and is at rest at point A. It goes down the slope. What is its
velocity at point B?
a.
b.
9.90 m/s
0.00 m/s
c.
d.
98.0 m/s
49.0 m/s
____ 15.
In this figure, the spring has a spring constant of 900 N/m. The hand compresses the block-spring system by
F , exerted on the block by the spring?
x= -0.20 meters. What is the force, ä
a.
b.
180 N
-180 N
c.
d.
3
4500 N
-4500 N
Name: ________________________
ID: A
____ 16.
In this figure, the spring has a spring constant of 900 N/m. The hand compresses the block-spring system by
x= -0.20 meters. What is the elastic potential energy stored in the spring?
____ 17.
____ 18.
____ 19.
____ 20.
____ 21.
____ 22.
____ 23.
____ 24.
a. 180 J
c. -18 J
b. 4500 J
d. 18 J
A child on a skateboard has a speed of 1 m/s. After a force is applied to the child, her speed is 3 m/s. What
can you say about the work done by the external force?
a. Positive work was done
c. No work was done
b. Negative work was done
d. Not enough information given
A car starts from rest and accelerates to 30 miles per hour (mph). Later it gets on the highway and
accelerates to 60 mph. Which takes more energy: accelerating from 0⇒30 mph or 30⇒60 mph?
c. both the same
a. 0⇒30 mph
b. 30⇒60 mph
Two paths lead to the top of a big hill. One is steep and direct while the other is twice as long but less steep.
How much more potential energy would you gain if you took the longer path?
a. twice as much
d. one-half as much
b. four times as much
e. you gain no potential energy
c. the same
How does the work required to stretch a spring 2 cm compare with the work required to stretch it 1 cm?
a. same amount of work
c. four times the work
b. twice the work
d. eight times the work
When you pay the electric company for so many kilowatt-hours, what exactly are you paying for?
a. power
d. voltage
b. energy
e. none of these
c. current
A car with mass 1000 kg has a speed of 10 km/hr. What is its momentum in SI units?
a. 10,000 kg m/s
c. 4,000 J
b. 3,000 kg m/s
d. 100 kg hr/km
In an elastic collision, which of these quantities are conserved
a. Momentum only
c. Velocity
b. Momentum & energy
d. Energy only
A football of mass 0.2 kg is thrown at a velocity of 10 m/s. A receiver catches the ball and brings it to rest in
0.01 seconds. What is the magnitude of the force imparted on the receiver?
a. 0.02 N
c. 2 N
b. 200 N
d. 20 N
4
Name: ________________________
ID: A
____ 25. A man of mass 99 kg holds a gun of 1 kg; the man and gun are initially at rest. The man fires the gun, and a
bullet of mass 10 grams emerges from the gun with a velocity of 300 m/s. What is the speed of the man and
gun after firing (i.e. the recoil speed)?
a. 0.03 m/s
c. 0.1 m/s
b. 300 m/s
d. 3 m/s
____ 26. An open cart rolls along a frictionless track while it is raining. As it rolls, what happens to the speed of the
cart?
a. speeds up
c. nothing
b. slows down
d. not enough information given
____ 27. A system of particles is known to have a total kinetic energy of zero. What can you say about the momentum
of the system?
a. momentum is positive
c. momentum is zero
b. momentum is negative
d. you can’t say anything about the
momentum
____ 28. A small car and large truck collide head-on and stick together. Which has the larger change in momentum?
a. the more massive truck
c. neither, they have the same change in
momentum
b. the less massive car
d. not enough information given
____ 29. What are the units for momentum?
c. Joules
a. N m
b. kg m/s
d. kg m/s2
____ 30. A small beanbag and a bouncy rubber ball are dropped from the same height above the floor. Which one will
impart the greater impulse to the floor when it hits?
a. the beanbag
c. both impart the same impulse
b. the rubber ball
d. not enough information given to answer
____ 31. Which of these is not a field force?
a. electric force
c. normal force
b. gravitational force
d. weak nuclear force
____ 32. Which of these is a measure of an object’s inertia?
a. mass
c. acceleration
b. force
d. velocity
____ 33. You are using version A of this test. Please bubble “A” here and write “Version A” next to your name on the
scantron.
a. A
c. C
b. B
d. D
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ID: A
Exam 2 -- PHYS 101
Answer Section
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