AP PHYSICS 1
KINEMATICS
THERE MIGHT BE MISTAKES
1. The graph above shows the velocity vs. time for an object moving in a straight line. At what time after time t = 0 does the object again pass through its initial position?
A. 1 second
B. Between 1 and 2 seconds C. 2 seconds
D. Between 2 and 3 seconds
2. A ball is thrown straight upward into the air. At the ball’s maximum altitude, where its velocity is zero, its acceleration is
A. Zero
B. Changing from upward to downward C. Changing from downward to upward D. Directed downward
Multi–Correct: Students will need to select all the correct answers to the question below in order to earn credit.
3. As a car is driven south in a straight line with decreasing speed, the acceleration of the car must be
A. directed northward B. directed southward C. zero
D. constant, but not zero
Questions 4 – 6 refer to five objects that start at x = 0 and
t = 0 and move in one dimension independently of one another. Graphs of the velocity vs. time are shown below.
4. Which object has traveled farthest from the origin at two seconds?
5. Which object moves with a constant nonzero acceleration?
6. Which object is in its initial position at two seconds?
7. An object moving in the positive direction passes the origin at time t = 0. Between t = 0 and t = 1 second, the object has a constant speed of 24 m/s. At t = 1 second, the object is given a constant acceleration of 6 m/s² in the negative direction. The position of the object at t = 11 seconds is
A. + 99 m B. + 36 m C. – 36 m D. – 75 m
0 + 1 . 0
v ( m / s )
– 1 . 0
1 . 0 2 . 0 t ( s )
O b je c t B
0 + 1 . 0
v ( m / s )
– 1 . 0
1 . 0 2 . 0 t ( s )
O b je c t D
0 + 1 . 0
v ( m / s )
– 1 . 0
1 . 0 2 . 0 t ( s )
O b je c t C
0 + 1 . 0
v ( m / s )
– 1 . 0
1 . 0 2 . 0 t ( s )
O b je c t E
t ( s ) 0
+ 1 . 0
v ( m / s )
– 1 . 0
1 . 0 2 . 0
Questions 7 and 8:
At time t = 0, Car X traveling with speed v0 passes Car Y, which is just starting to move. Both cars then travel on parallel lanes of the same straight road. The graphs of speed vvs. time t for both cars are shown above.
8. Which of the following is true at time t = 20 seconds?
A. Car Y is behind Car X. B. Car Y is passing Car X. C. Car Y is in front of car X.
D. Both cars have the same acceleration.
9. From time t = 0 to t = 40 seconds, the areas under both graphs are equal. Therefore, which of the following is true at time t = 40 seconds?
A. Car Y is behind Car X. B. Car Y is passing Car X. C. Car Y is in front of car X.
D. Both cars have the same acceleration.
10. An object’s speed is decreasing
A. Any time its velocity has a negative magnitude. B. Only if its acceleration is negative.
C. If its velocity and acceleration have the same direction.
D. If its velocity and acceleration have opposite directions.
Questions 11 and 12:
11. The displacement x of an object moving along the
x axis is shown above as a function of time t. The acceleration of the object must be
A. Zero
B. Constant but not zero C. Increasing
D. Decreasing
12. The velocity of the object must be
A. Zero
B. Constant but not zero C. Increasing
D. Decreasing
The graph above represents the velocity-time graph for two objects, A and B.
Which of the following statements is true?
A. Over the first four seconds, object B has an average velocity of 5 m/s.
B. At t = 4 s, both objects have covered the same distance.
C. Object A is motionless.
14. An object moving in the positive direction passes the origin at time t = 0. Between t = 0 and t = 1 second, the object has a constant speed of 24 m/s. At t = 1 second, the object is given a constant acceleration of 6 m/s² in the negative direction. The position of the object at t = 11 seconds is
E. + 99 m F. + 36 m G. – 36 m H. – 75 m
Consider the following graphs, noting the different axes.
Which of these represent(s) motion at constant, non-zero acceleration?
A. I, II, and IV B. I and III C. II and V D. V only
1. A block of mass 3m can move without friction on a horizontal table. This block is attached to another block of mass m by a cord that passes over a frictionless pulley, as shown above. What is the magnitude of the acceleration of the falling block?
A. Zero B. g/4 C. g/3 D. g
2. A push broom of mass m is pushed across a rough horizontal floor by a force of magnitude T directed at angle as shown above. The coefficient of friction between the broom and the floor is . The frictional force on the broom has magnitude
A. ( mg + T sin ) B. ( mg – T sin ) C. ( mg + T cos ) D. ( mg – T cos )
3. When an object is suspended from two equal length strings as shown, the vertical component of the tension in each string is
4. The parabola above is a graph of distance as a function of time for a moving object. Which of the following graphs best represents the magnitude of the net force exerted on the object as a function of time?
D
5. A rope of negligible mass supports a block that weighs 30 N, as shown above. The breaking strength of the rope is 50 N. The largest acceleration that can be given to the block by pulling up on it with the rope without breaking the rope is most nearly
A. 6 m/s² B. 6.7 m/s²
C. 10 m/s² D. 16.7 m/s²
6. A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed v. The constant horizontal force applied by the woman
A. Has the same magnitude as the weight of the box.
B. Is greater than the weight of the box.
C. Has the same magnitude as the total force which resists the motion of the box.
D. Is greater than the total force which resists the motion of the box.
7. If the woman in the previous question suddenly stops applying the horizontal force to the box, the box will
A. Immediately come to a stop.
B. Continue moving at a constant speed for a while and then slow to a stop.
C. Immediately start slowing to a stop. D. Continue at a constant speed.
.
Multi–Correct: Students will need to select all the correct answers to the question below in order to earn credit.
8. Three forces act on an object. If the object is in equilibrium, which of the following must be true?
A. The vector sum of the three forces must equal zero.
B. The magnitudes of the three forces must be equal.
C. All three forces must be parallel. D. The object must be at rest.
1. From the top of a high cliff, a ball is thrown horizontally with initial speed v0. Which of the following graphs best represents the ball’s kinetic energy K as a function of time t ?
F
t F
t F
t F
A .
C . D .
E .
t t
2. An ideal spring obeys Hooke’s law, F = –k x. A mass of 0.50 kilogram hung vertically from the spring stretches the spring 0.075 meter. The value of the force constant for the spring is most nearly
A. 0.66 N/m B. 6.6 N/m C. 33 N/m D. 66 N/m
3. A student weighing 700 N climbs at constant speed to the top of an 8 m vertical rope in 10 s. The average power expended by the student to overcome gravity is most nearly
A. 87.5 W B. 560 W C. 875 W D. 5,600 W
4. An object is dropped from rest from a certain height. Air resistance is negligible. After falling a distance d, the object’s kinetic energy is proportional to which of the following?
A. 1
d
B.
√
dC. d D. d²
9. For a block of mass m to slide without friction up a rise of height h, the minimum initial speed of the block must be
A.
√
gh2
B.
√
gh
2
C.
√
2ghD. 2
√
gh5. A rock of mass m is thrown horizontally off a building from a height h, as shown above. The speed of the rock as it leaves the thrower’s hand at the edge of the building is v0. What is the kinetic energy of the rock just before it hits the ground?
A. mgh
B. 1
2m v0
2
C. 1
2m v0
2 +mgh
D. mgh−1
2m v0
2
6. A constant force of 900 N pushes a 100 kg mass up the inclined plane shown above at a uniform speed of 4 m/s. The power developed by the 900 N force is most nearly
10. A cart of mass 5.0 kg is moving horizontally in a straight line at 6.0 m/s. In order to change its speed to 10.0 m/s, the work done on the cart must be
A. 40 joules B. 90 joules C. 160 joules D. 400 joules
11. A box is pushed to the right with a varying horizontal force. The graph above represents the relationship between the applied force and the distance the box moves. What is the total work done in moving the box 6.0 meters?
A. 0.0 J B. 9.0 J C. 18 J D. 27 J
12. As shown in the diagram above, a child applies a constant 20 newton force along the handle of a wagon which makes a 25° angle with the horizontal. How much work does the child do in moving the wagon a horizontal distance of 4.0 meters?
A. 5.0 J B. 34 J C. 73 J D. 80 J
3. A system consists of two objects having masses ml and m2 (ml < m2). The objects are connected by a massless string, hung over a pulley as shown above, and then released. When the speed of each object is v, the magnitude of the total linear momentum of the system is
A. (m1 + m2) v B. (m2 – m1) v C. ½(ml + m2) v D. ½(m2 – m1) v
5. A tennis ball of mass m rebounds from a racquet with the same speed v as it had initially. as shown above. The magnitude of the momentum change of the ball is
A. 0 B. 2mv
4. Two objects, A and B, initially at rest, are “exploded” apart by the release of a coiled spring that was compressed between them. As they move apart, the velocity of object A is 5 m/s and the velocity of object B is –2 m/s. The ratio of the mass of object A to the mass of object B, mA / mB, is
A. 4/25 B. 2/5 C. 5/2 D. 25/4
F ( N )
0 t ( s )
2
1
1 2 3 4 5
6. A 2.0 kg object initially moving with a constant velocity is subjected to a force of magnitude F in the direction of motion. A graph of F as a function of time t is shown above. What is the increase, if any, in the velocity of the object during the time the force is applied?
A. 0 m/s B. 3.0 m/s C. 4.0 m/s D. 6.0 m/s
7. How does an air mattress protect a stunt person landing on the ground after a stunt?
A. It reduces the momentum change of the stunt person.
B. It increases the momentum change of the stunt person.
C. It shortens the stopping time of the stunt person and increases the force applied during the landing. D. It lengthens the stopping time of the stunt person
8. As shown above, two students sit at opposite ends of a boat that is initially at rest. The student in the front throws a heavy ball to the student in the back. What is the motion of the boat at the time immediately after the ball is thrown and, later, after the ball is caught? (Assume that air and water friction are negligible.)
Immediately
After the Throw After the Catch A. Boat moves forward Boat moves backward B. Boat moves forward Boat does not move C. Boat moves backward Boat does not move D. Boat moves backward Boat moves forward
1 . 5 k g
4 . 0 k g 2 . 0 m / s
1 . 0 m / s
9. Two pucks moving on a frictionless surface are about to collide, as shown above. The 1.5 kg puck is moving directly east at 2.0 m/s. The 4.0 kg puck is moving directly north at 1.0 m/s. What is the magnitude of the total momentum of the two-puck system after the collision?
A. 1.0 kg·m/s B. 5.0 kg·m/s C. 7.0 kg·m/s
D.
5.5
√
5
kg·m/s10. An open cart on a level surface is rolling without frictional loss through a vertical downpour of rain, as shown above. As the cart rolls, an appreciable amount of rainwater accumulates in the cart. The speed of the cart will
A. increase because of Newton’s Second Law B. increase because of conservation of momentum C. decrease because of conservation of momentum D. remain the same because the raindrops are falling
perpendicular to the direction of the cart’s motion
11. Three objects can only move along a straight, level path. The graphs below show the position d of each of the objects plotted as a function of time t.
The magnitude of the momentum of the object is increasing in which of the cases?
(A) II only (B) III only (C) I and II only (D) I and III only (E) I, II, and III
12. The two blocks of masses M and 2M shown above initially travel at the same speed v but in opposite directions. They collide and stick together. How much mechanical energy is lost during the collision? (A) Zero
(B) ½ Mv² (C) ¾ Mv² (D)4/
3Mv² (E) 3/
2Mv²
velocity of object A is 5 m/s and the velocity of object B is –2 m/s. The ratio of the mass of object A to the mass of object B, mA / mB, is
E. 4/25 F. 2/5 G. 5/2 H. 25/4
F ( N )
0 t ( s )
2
1
1 2 3 4 5
13. A 2.0 kg object initially moving with a constant velocity is subjected to a force of magnitude F in the direction of motion. A graph of F as a function of time t is shown above. What is the increase, if any, in the velocity of the object during the time the force is applied?
