Chapter 3 Force
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
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1. When constructing a graph, the x-axis is most closely related to:
a. the dependent variable.
b. the vertical axis.
c. the independent variable.
d. the slope.
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2. A rocket sled accelerates from 10 m/sec to 50 m/sec in 2 seconds. What is the
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3.
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4.
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5.
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6.
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7.
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8.
acceleration of the sled?
a. 10 m/sec2
b. 25 m/sec2
c. 40 m/sec2
d. 20 m/sec2
Objects tend to resist changes in motion. This property is called:
a. weight.
b. momentum.
c. potential energy.
d. inertia.
Compared to your weight and mass on Earth, if you were on the moon:
a. your weight and mass would be less.
b. your weight would be less but your mass would remain the same.
c. your weight would remain the same, but your mass would be less.
d. your weight would increase, but your mass would remain the same.
Newton's first law of motion is also known as:
a. the law of universal gravitation.
b. the law of force pairs.
c. the law of unbalanced forces.
d. the law of inertia.
A net force must be applied to an object to do all of the following EXCEPT:
a. turn.
b. maintain constant speed.
c. slow down.
d. stop moving.
A cart is rolling down a ramp. If the angle of the ramp is increased to make the ramp
steeper, the cart will:
a. accelerate slower.
b. accelerate at the same rate.
c. accelerate faster.
d. move at a constant velocity.
What is the mass of a rock that weighs 49 newtons?
a. 1 kilogram
b. 2 kilograms
c. 5 kilograms
d. 10 kilograms
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9. A tow truck pulls a 2,000-kilogram car with a net force of 4,000 newtons. What is the
acceleration of the car?
a. 0.5 m/sec2
b. 2 m/sec2
c. 200 m/sec2
d. 2,000 m/sec2
____ 10. In the picture below, a girl is sitting motionless on a swing. What is the net force on the
girl?
a.
b.
c.
d.
0 newtons
245 newtons upwards
490 newtons upwards
490 newtons downwards
____ 11. A potato launcher uses a spring that can apply a force of 20 newtons to potatoes. A
physics student who is studying projectiles launched a 100-gram potato, a 150-gram
potato, and a 200-gram potato with the launcher. Which had the greatest acceleration?
a. The 100-gram potato.
b. The 150-gram potato.
c. The 200-gram potato.
d. They all had the same acceleration.
____ 12. A 200-kilogram rocket accelerates at 50 m/sec2. How large is the force required to cause
an acceleration of this size?
a. 1/4 newton
b. 4 newtons
c. 1,000 newtons
d. 10,000 newtons
____ 13. A car is traveling down a straight stretch of highway at 90 kilometers per hour. The
driver suddenly slams on the brakes and brings the car to a quick stop. As a result, the
unbelted passengers will at first:
a. continue to move forward in a straight line.
b. come to a stop at the same time as the car.
c. be pushed against the door on the passenger side.
d. be pushed against the back of the seat.
____ 14. On the surface of Earth, the force of gravity acting on one kilogram is:
a. 22 pounds
b. 9.8 pounds
c. 2.2 newtons
d. 9.8 newtons
____ 15. As a box is sliding down a ramp, a 10 newton force of gravity is pulling the box down the
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ramp while a 2 newton force of friction acts to stop the box. What is the net force
accelerating the box down the ramp?
a. 5 newtons
b. 8 newtons
c. 10 newtons
d. 12 newtons
The acceleration due to gravity is approximately 10 m/sec2. If a golf ball is dropped from
the thirteenth floor of a building, ignoring air resistance, after falling for 3 seconds the
speed of the ball will be:
a. 10 m/sec.
b. 15 m/sec.
c. 30 m/sec.
d. 45 m/sec.
A cart is rolling down a special ramp where there is no friction at all. What will happen if
the amount of mass on the cart is increased?
a. The cart will accelerate less.
b. The cart's acceleration will not be affected.
c. The cart will accelerate more.
d. The cart will move at a constant velocity.
What is the approximate weight in newtons of a 7.0-kilogram bowling ball?
a. 7.0 newtons
b. 70 newtons
c. 700 newtons
d. 7000 newtons
The force of friction acting on a cart on a ramp is exactly balanced by the force of gravity
acting on the cart down the ramp. The cart:
a. must be stationary.
b. may be accelerating down the ramp.
c. may be moving with constant speed down the ramp.
d. must be moving with constant speed down the ramp.
A book rests on a table. The force of gravity pulls down on the book with a force of 20
newtons. What prevents the book from accelerating downward at 9.8 m/sec2?
a. The table presses back up on the book with an equal and opposite force of 20
newtons.
b. The table presses back up on the book with a force greater than 20 newtons.
c. The table and the book together are accelerating downwards at 9.8 m/sec2.
d. The inertia of the book holds it up.
____ 21. A rocket can fly into space because:
a. when it is launched, the hot exhaust gases hit the ground and push the rocket
forward.
b. the rocket pushes the exhaust gases backward, and there is an equal and opposite
reaction pushing the rocket forward.
c. when the gases are burning up, the mass of the rocket decreases, changing the
amount of gravity on the rocket.
d. the launch pad pushes the rocket forward like a slingshot.
____ 22. Newton's third law of motion involves:
a. one force acting on one object.
b. a force pair acting on two different objects.
c. a force pair acting on one object.
d. unbalanced forces acting on many objects.
____ 23. A stationary object has:
a. both inertia and momentum.
b. neither inertia nor momentum.
c. momentum but no inertia.
d. inertia but no momentum.
____ 24. An astronaut with a mass of 100 kilograms is floating in outer space. If the astronaut
throws a 2-kilogram wrench at a speed of 10 meters per second, his motion would best be
described as:
a. in the same direction as the wrench at a speed less than 10 m/sec.
b. in the same direction as the wrench at a speed greater than 10 m/sec.
c. in a direction opposite to the wrench at a speed less than 10 m/sec.
d. in a direction opposite to the wrench at a speed greater than 10 m/sec.
____ 25. What is the momentum of a 0.15-kilogram baseball moving at 20 m/sec?
a. 1.5 kg·m/sec
b. 3 kg·m/sec
c. 15 kg·m/sec
d. 30 kg·m/sec
____ 26. A 0.15-kilogram baseball and a 7.25-kilogram bowling ball are both rolling along at 3
m/sec. Which object is easier to stop and why?
a. The bowling ball because it has less inertia
b. The baseball because it has more inertia
c. The bowling ball because heavy objects are naturally prone to stop on their own
d. The baseball because it has less inertia
If you do not show your work, you will not get partial credit.
Please Box your final answer to each question.
27) Steve is running carrying the ball towards the end zone
with a force of 109 N. One defender is standing in his way.
He has a mass of 71.3 kg, and an acceleration of 1.34 m/s2 .
What is the defender’s force and does Steve score a
touchdown? (hint: If Steve’s force is greater- he scores)
28)
Mr. O jumps 1.35 meters from the top of a wall
on his unicycle. He has a mass of 95.3 kg. What is Mr.
O’s force? ( the acceleration due to gravity is 9.8 m/s2
)
29)
What is the mass of a bullet when it is fired with
a force of 10755 N, which has a final speed of 112 m/s,
and happens in .0053 seconds? (Hint: calculate the
acceleration, then plug that into the force equation)
30)
What is the momentum of a 23.okg ball rolling at
13m/s?
Questions 31 to 35 all relate to the following problem:
Mike has a mass of 30kg and stands on a skateboard at
rest. He throws a 5.0kg rock at a velocity of 10.0m/s off
of the skateboard.
31)
32)
What is the total momentum before the collision?
What is the momentum of the rock after it is
thrown?
33)
What is mike’s momentum after the rock is thrown?
34)
What is mike’s speed after he throws the rock?
35)
What is the impulse?
F  ma
Impulse = change in momentum of an object
Chapter 3 Force
Answer Section
MULTIPLE CHOICE
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C
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B
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A
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A
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B
C
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B
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B
D