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AP Physics Newton's Laws Practice Test

Answers: A,D,C,D,C,E,D,B,A,B,C,C,A,A 15. (b) both are 2.8 m/s 2 (c) 22.4 N (d) 1 s, 2.8 m/s 16. (a)

12.5 N, 3.54 m/s 2 (b) 5.3 kg

_____1. Two blocks are pushed along a horizontal frictionless surface by a force of 20 N to the right, as shown above. The force that the 2 kilogram block exerts on the 3 kilogram block is

A. 8 N to the left

B. 8 N to the right

C. 10 N to the left

D. 12 N to the right

E. 20 N to the left

_____2. An elevator is pulled up by a cable with a force of 65,000 N. The upward acceleration of the elevator is 1.8 m/s/s. What is the mass of the elevator?

A. 1.8 kg.

B. 1700 kg.

C. 54880 kg.

D. 5600 kg.

E. 36111 kg.

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.

_____3. Which of the following best indicates the direction of the acceleration, if any, of the ball at point Q ?

(A) (B)

(C)

(D)

(E) There is no acceleration of the ball at point Q.

_____4. Which of the following best indicates the direction of the net force on the ball at point P ?

(A) (B) (C) (D) (E)

_____5. If F

1

is the magnitude of the force exerted by the Earth on a satellite in orbit about the Earth and F

2

is the magnitude of the force exerted by the satellite on the Earth, then which of the following is true?

(A) F

1

is much greater than F

2

. (B) F

1

is slightly greater than F

2

.

(C) F

1

is equal to F

2

. (D) F

2

is slightly greater than F

1

(E) F

2

is much greater than F

1

1

_____6. A 80 N horizontal force is applied to a 20.0 kg block at rest on a horizontal surface where µ

S

=

0.6. What is the magnitude of the force of friction on the block?

A. 118 N.

B. 12 N.

C. 33 N.

D. 100 N.

E. 80 N.

_____7. A 40 kg box is dragged across a frictionless horizontal surface by a rope. The tension in the rope is 65 N and it is at an angle of 42o to the horizontal. What is the box's acceleration?

A. 1.6 m/s

2

.

B. 1.1 m/s

2

.

C. 0.6 m/s

2

.

D. 1.2 m/s

2

.

E. 0.9 m/s

2 .

_____8. A 4.4 kg block sits on a horizontal surface. If µs = 0.4, what is the minimum force to get the block to start to slide?

A. 8.6 N.

B. 17.2 N.

C. 43.2 N.

D. 26.4 N.

E. 57.0 N.

**_____9. The figure shows two horizontal forces acting on a block along a frictionless floor. Assuming that a third horizontal force F**

3

** also acts on the block. What are the magnitude and direction of F**

3

when the block is moving to the left with a constant velocity of 8 m/s?

A. 8 N to the right.

B. 8 N to the left.

C. 4 N to the right.

D. 4 N to the left.

E. need block's mass to answer.

2

_____10. A block of mass 5 kilograms lies on an inclined plane, as shown above. The horizontal and vertical supports for the plane have lengths of 4 meters and 3 meters, respectively. The coefficient of kinetic friction between the plane and the block is 0.3. The magnitude of the force F necessary to pull the block up the plane with constant speed is most nearly

(A) 30 N (B) 41 N (C) 49 N

(D) 50 N (E) 58 N

____11. You are driving down the road when a fruitfly gets splattered on your windshield. Which of the following is correct?

A. The fruitfly experienced a greater force than the windshield.

B. The windshield experienced a greater force than the fruitfly.

C. Each experienced the same force.

D. Each experienced the same acceleration.

E. Both A and D.

F. Both C and D.

_____12. What is the acceleration of a block on a ramp inclined 35 o to the horizontal if µk = 0.4?

A. 3.5 m/s2.

B. 0.9 m/s2.

C. 2.4 m/s2.

D. 9.8 m/s2.

E. not enough information given.

_____13. Solve for the mass of block M2 below. The pulley is frictionless. M1 = 6 kg, and M2 accelerates upward at 2.9 m/s/s.

A. 3.2 kg.

B. 4.8 kg.

C. 6.6 kg.

D. 9.8 kg.

E. 11.0 kg.

_____14. Solve for the tension in the rope in Figure 1.

A. 41.4 N.

B. 28.5 N.

C. 76.2 N.

D. 58.6 N.

E. 107.8 N

M1 M2

3

15. (8 Points) Answer the following questions for the two block system shown below. The horizontal surface is frictionless. M1 = 8 kg, M2 = 3.2 kg, and h = 1.4 m.

M1

M2 h

(a) Draw free body diagrams of M1 and M2 below. Draw and label all the forces acting on them and indicate your coordinate systems.

(b) The system is released from rest. Determine the accelerations of block M1 and block M2.

(c) Determine the tension in the string connecting block M1 to block M2.

(d) Determine the time it takes M2 to hit the floor and the speed it has just before hitting the floor.

4

16. (10 Points) Block m

1

in the figure below has a mass of 6 kg and m

2

has a mass of 1.4 kg. The coefficient of kinetic friction between m

2

and the horizontal surface is 0.55. The inclined plane is frictionless. m

2 m

1

!

= 35 o

(a) Find the tension in the cord and the acceleration of m

1

.

(b) If the coefficient of static friction is 0.65, what is the minimum mass of block m

2

that would prevent the system from moving.

5