AP Physics – Newton’s Laws - Multiple choice review
Ans: B E B B D C A E E D B C D D B C D C C D B D B
1. A car slides up a frictionless inclined plane. How does the normal force of the incline on the car compare
with the weight of the car?
a. The normal force must be equal to the car’s weight
b. The normal force must be less than the car’s weight.
c. The normal force must be greater than the car’s weight
d. The normal force must be zero
e. The normal force could have any value relative to the car’s weight.
2. In the diagram a 1.0 kg cart and a 2.0 kg cart are connected by a rope. The spring scale reads 10 N. What is
the tension in the rope connecting the two carts. Neglect any friction.
a. 30 N
b. 10 N
c. 6.7 N
d. 5.0 N
e. 3.3 N
3. The velocity time graph above represents the motion of a 5 kg box. The only force applied to this box is a
person pushing. Assuming that the box is moving to the right, what is the magnitude and direction of the force
applied by the person pushing
a. 2.0 N, right
b. 2.0 N, left
c. 0.4 N, right
d. 0.4 N, left e. 12.5 N, left
4. A person standing on a horizontal floor feels two forces: the downward pull of gravity and the upward
supporting force from the floor. These two forces
a. have equal magnitudes and form an action/reaction pair
b. have equal magnitudes but do not form an action/reaction pair
c. have unequal magnitudes and form an action/reaction pair
d. have unequal magnitudes and do not form an action/reaction pair
5. A person who weighs 800 N steps onto a scale that is on the floor of an elevator car. If the elevator
accelerates upward at a rate of 5 m/s2, what will the scale read?
a. 400 N
b. 800 N
c. 1000 N
d. 1200 N
e. 1600 N
6. A 20 N block is being pushed across a horizontal table by an 18 N force. If the coefficient of kinetic friction
between the block and the table is 0.4, find the acceleration of the block.
a. 0.5 m/s2
b. 1 m/s2
c. 5 m/s2
d. 7.5 m/s2
e. 9 m/s2
7. The coefficient of static friction between a box and a ramp is 0.5. The ramp’s incline angle is 30o. If the box is
placed at rest on the ramp, the box will do which of the following?
a. Accelerate down the ramp
b. Accelerate briefly down the ramp but then slow down and stop
c. Move with constant velocity down the ramp
d. Not move
e. It cannot be determined from the information given
8. Assuming a frictionless, massless pulley determine the acceleration of the blocks once they are released.
9. If all the forces acting on an object balance so that the net force is zero, then
a. the object must be at rest
b. the object will slow down
c. the object will follow a parabolic path
d. the object’s direction of motion can change, but not its speed
e. none of the above are always true
10. A block with mass m is rest on a frictionless horizontal table placed in a laboratory on the surface of the
Earth. An identical block is at rest on a frictionless, horizontal table placed on the surface of the moon. Let F be
the net force necessary to give the Earth-bound block an acceleration a across the table. Given that gmoon to
one-sixth gearth, the force necessary to give the Moon-bound block the same acceleration a across the table is
a. F/12
b. F/6
c. F/3
d. F
e. 6F
11. Railroad cars that carry gravel are loaded by being moved slowly under a chute through which the gravel
pours into the top of the car. As the gravel is loaded onto the train, what happens to the trains inertia?
a. it decreases
b. it increases
c. it is unchanged. The train is moving at a constant speed under the chute
d. it is unchanged. The train’s inertia depends on the weight of the engine
12. A chair weighs 300 N. A person sitting in the chair weighs 800 N. How much force does the floor exert on
the chair while the person sits in it?
a. 500 N
b. -500 N
c. 1100 N
d. 110 N
13. During an experiment you notice that s cart’s acceleration increases with each trial. The cart is kept the
same in each trial and moves on the same path in each trial. What is happening to the cart?
a. The friction is decreasing
b. The reaction force of the cart is decreasing
c. The mass of the mass is increasing
d. The applied force moving the cart must be increasing
14. A wooden bottom sled loaded with cinder blocks is pulled across a wooden floor several times. You notice
that each time you do this the force you exert becomes less as you take block off the sled. What is happening
to the coefficient of friction as you do this?
a. it increases
b. it decreases
c. it is unchanged. The friction is unrelated to the weight of the sled
d. it is unchanged. The coefficient of friction indicates the nature of the two surfaces.
15. A lawnmower is being pushed by a handle that is at an angle with the horizontal. As the angle that the
handle is pushed is decreased, what happens to the normal force the ground presses on the wheels of the
lawn mower with?
a. it increases
b. it decreases
c. it is unchanged. The normal force depends on the force of friction
d. it is unchanged. The normal force depends only on the weight of the lawnmower
e. The normal force becomes zero
16. A person who normally weighs 600 N is standing on a scale in an elevator. The elevator is currently moving
down at a constant velocity. What is the current reading on the scale in the elevator?
a. 0 N
b. some amount less than 600 N
c. 600 N
d. some amount more than 600 N
17.
18. You are driving down the road when a fruitfly gets splattered on your windshield. Which of the following is
correct?
a. The fruitfly experience a greater force than the windshield
b. The windshield experienced a greater force than the fruitfly
c. Each experienced the same force
d. Each experience the same acceleration
e. both C and D
A ball is thrown and follows a parabolic path, as shown above. Air friction is negligible. Point Q is the highest
point on the path. Use the diagram for questions 19 and 20
19. Which of the following best indicates the direction of the acceleration, if any, of the ball at point Q?
(E) There is no acceleration at point P
20. Which of the following best indicates the direction of the net force on the ball at point P?
21. The coefficient of kinetic friction between the ground and a sled is 0.25. If the sled’s mass is 8.0 kg, how
much force is required to move the sled at a constant velocity?
a. 2.0 N
b. 20 N
c. 320 N
d. 32 N
e. 54 N
22. Three boxes slide on a frictionless horizontal surface when pulled by a force of magnitude F. When we
compare the tensions T1 and T2 with the force F, we find that
23. A student pushes a big 16 kg box across the floor at
a constant speed. He pushes with a force of 50 N angled
35o from the horizontal, as shown in the diagram. If the
student pulls rather than pushes the box at the same
angle, while maintaining a constant speed, what will
happen to the force of friction?
a. It must increase
d. It will increase only if the speed is greater than 3.1 m/s
b. It must decrease
e. It will increase only if the speed is less than 3.1 m/s
c. It must remain the same