AP Physics I – Practice Test #1 Notes on the actual exam:  Date: Tuesday May 2nd, 12:00 noon Format of Assessment Section I: Multiple Choice: 50 Questions | 90 Minutes | 50% of Exam Score

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Discrete items Items in sets Multi-select items (two options are correct) Section II: Free Response: 5 Questions | 90 Minutes | 50% of Exam Score

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Experimental Design (1 question) Quantitative/Qualitative Translation (1 question) Short Answer (3 questions, one requiring a paragraph-length argument)

NAME: _________________________________

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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AP Physics 1 Week 1 Practice MC Kinematics, Momentum, COM 1. Two objects are to fall straight downward under the influence of gravity with an acceleration g. Object 1 is released from rest and object 2 is thrown downward from a somewhat greater height with an initial velocity va. Graphs of their motion are shown. The second object catches up with the first object at time T. Which of the following expressions correctly describes the initial difference in heights? A. vaT B. (vb  va) T C. ½ (va + vb) T

D. ½ gT2 + vaT

2. A student is running at a constant speed toward a ball that is rolling directly toward him but slowing down. The student arrives at the ball and kicks it in the same direction that the student was moving. Which of the following sets of graphs shows a reasonable representation of the positions of the student and the ball?

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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3. The above graph shows the acceleration as a function of time. Which of the following correctly ranks the change in velocity, v, for each time interval? A. vAB < vBC < vCD < vDE B. vAB < vCD < vBC < vDE C. vDE < vAB < vBC < vCD D. vAB < vBC < vDE < vCD

4. A chain is hanging over the edge of a frictionless table. It is released and falls to the ground. Which of the following graphs would best represent its velocity from the moment it is released to the moment it strikes the ground?

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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5. Starting at the same position two toy cars are moving to the right along straight lines. The graph above shows their velocities as a function of time. During what time interval, after t = 0s does one car pass the other? A. tA to tB B. tB to tC C. tC to tD D. They do not pass in this time period.

6. As shown above, a student stands on a cart that is free to roll with no friction. On the cart is a rigidly attached wall. The student throws a heavy ball at the wall. Consider three possible situations. I. The ball is made of clay, hits the wall and sticks to it. II. The ball is made of rubber, hits the wall, rebounds, and the student catches it. III. The ball is made of rubber, hits the wall, rebounds, and the student fails to catch it. For which if any, of these cases will the cart and student gain a net motion to the right? A. I B. II C. III D. None of these

7. A net force F is applied to a 2.0 kg object that is initially moving at 3.0 m/s. The Force varies as shown in the graph above. The speed of the object at the end of the 4.0 s time interval is closest to which of the following? A. 5.0 m/s B. 7.0 m/s C. 10 m/s D. 14 m/s AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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8. A block of width W is located inside of the right side of a box of length L. The block and box are of equal mass, M, and are initially at rest. The surface between the block and box is frictionless. An external force F is applied to the box that accelerates while the block slides until it strikes the left end of the box. During that time period what distance will the block + box system’s center of mass have moved? A. L  w w B. L  2 L C. w 2 L w D.  2 2

9. The velocity of a projectile at launch has a horizontal component vh and a vertical component vv. Air resistance is negligible. When the projectile is at the highest point of its trajectory, which of the following shows the vertical and horizontal components of its velocity and the vertical component of its acceleration? Vertical Horizontal Vertical Velocity Velocity Acceleration (A) vv vh 0 (B) 0 vh 0 (C) 0 0 g (D) 0 vh g

10. Of the following, which does not involve an assumption about the equivalence of inertial and gravitational mass? Gm planet A. The centripetal acceleration of a satellite is given by a  r2 B. At a point on the earth’s surface the freefall acceleration of all objects is the same. m C. The period of oscillation for an object suspended from a spring is given by TS  2 k D. The acceleration of a given object pulled across a surface is given by a force, F, is given by AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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a

F   k mg m

11. The above table gives information about two small solid particles that will be involved in a collision. Upon collision, the two particles bounce off each other and go their separate ways. Which two of the following tables provide information that could be the possible result of the collision?

12. A 0.2 kg rock is dropped into a lake from a few meters above the surface of the water. The rock reaches terminal velocity in the lake after 5 s in the water. During the final 3 s of its descent to the lake bottom, the rock moves at a constant speed of 4 m/s. Which of the following can be determined from the information given? Select two answers. A. The speed of the rock as it enters the lake B. The distance the rock travels in the first 5 s of its descent in the water C. The acceleration of the rock 2 s before it reaches the lake bottom D. The change in potential energy of the rock-Earth-water system during the final 3 s of the rock’s descent.

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Questions 13 – 15 refer to the following material. Block 1 of mass m1 and block 2 of mass m2 are sliding along the same line on a horizontal frictionless surface when they collide at time tc. The graph shows the velocities of the blocks as a function of time.

13. Which block has the greater mass, and what information indicates this? A. Block 1, because it had a greater speed before the collision. B. Block 1, because the velocity after the collision is in the same direction as its velocity before the collision. C. Block 2, because it had a smaller speed before the collision. D. Block 2, because the final velocity is closer to the initial velocity of block 2 than it is to the initial velocity of block 1.

14. How does the kinetic energy of the two-block system after the collision compare with its kinetic energy before the collision, and why? A. It is less, because the blocks have the same velocity after the collision, so some of their kinetic energy was transformed into internal energy. B. It is less, because the blocks have velocities in opposite directions before the collision, so some of their kinetic energy cancels. C. It is the same, because the collision was instantaneous, so the effect of external forces during the collision is negligible. D. It is the same, because the blocks have the same velocity after the collision, ant there is no friction acting on them.

15. Which of the following is true of the motion of the center of mass of the two-block system during the time shown? A. The center of mass does not move because the blocks are moving in opposite directions before the collision. B. The center of mass moves at a constant velocity of +1.0 m/s because there is no friction acting on the system. C. The center of mass velocity starts out greater than +1.0 m/s but decreases to +1.0 m/s during the collision because the collision is inelastic. D. The center of mass velocity increases as the blocks get closer together, and then becomes constant after the collision. AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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AP Physics 1 Week 1 Free Response Practice 1 Mechanics, Momentum

1978B2(modified). A block of mass M1 travels horizontally with a constant speed vo on a plateau of height H until it comes to a cliff. A toboggan of mass M2 is positioned on level ground below the cliff as shown above. The center of the toboggan is a distance D from the base of the cliff so that the block lands in the center of the toboggan. (a) If the block were allowed to leave the cliff at the same speed (of magnitude vo) at a small angle above the horizontal or at a small angle below the horizontal, rank the distances for the placement of the toboggan so that the block will still land in the center of the toboggan. D is the distance from the cliff when the block leaves horizontally, Dabove is the distance when the block leaves with a velocity above the horizontal, and Dbelow is the distance when the block leaves with a velocity below the horizontal. If any distances are the same, give them the same ranking. (1 = smallest distance from edge of cliff, 3 = largest distance from edge of cliff) __________ D Explain your reasoning in words.

__________ Dabove

__________ Dbelow

(b) If the velocity of the block were to be increased so that it leaves the cliff horizontally with a velocity v1 greater than vo, how does the corresponding distance D1 for the block to land in the toboggan compare to the original distance D? _____ D1 < Do _____ D1 > Do _____ D1 = Do Explain your reasoning in words.

(c) Determine the distance D from the base of the cliff in terms of vo, H, and g so that the block lands in the center of the toboggan.

(d) When the block lands on the toboggan, it sticks to the toboggan in an inelastic collision. The toboggan is free to slide without friction on the ground below the cliff. Determine the resulting velocity of the block and toboggan.

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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1991M1 Experiment Design In a laboratory experiment, you wish to determine the initial speed v0 of a dart just after it leaves a dart gun. At your lab table you have only the following equipment. Meter stick Stopwatch Dart of mass m Protractor 5 m of string block of wood of mass M0 Dart Gun Spring of known spring constant k (a) Select the equipment you need and design (write a procedure for) an experiment to determine the speed of the dart. Draw a diagram explicitly labeling what you plan to measure, and create a data table in which you could record the measurements (include both a symbol for each measurement and the unit label appropriate for that measurement.

(b) Determine the equation needed to calculate the v0 of the dart and express it in the terms of m, M0, appropriate fundamental constants, and the symbols of the data in your data table.

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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1990B1  AP 1 Paragraph Answer A bullet of mass m is moving horizontally with speed vo when it hits a block of mass 100m that is at rest on a horizontal frictionless table, as shown above. The surface of the table is a height h above the floor. In Scenario 1 the bullet and the block slide off the table and hit the floor a distance x from the edge of the table. In Scenario 2 the bullet passes through the block instead of remaining in it. In which scenario will the block land at a greater distance “x” from the table. Justify your answer with a paragraph length response. Equations may be part of your justification but are not sufficient by themselves.

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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AP Physics 1 Week 1 Free Response Practice 2 Mechanics, Momentum 2006B2. A world-class runner can complete a 100 m dash in about 10 s. Past studies have shown that runners in such a race accelerate uniformly for a time t and then run at constant speed for the remainder of the race. A world-class runner is visiting your physics class. You are to develop a procedure that will allow you to determine the uniform acceleration a and an approximate value of t for the runner in a 100 m dash. By necessity your experiment will be done on a straight track and include your whole class of eleven students. (a) Outline the procedure that you would use to determine a and t, including a labeled diagram of the experimental setup. Use symbols to identify carefully what measurements you would make including any pieces of equipment.

(b) Describe the process of data analysis, including how you will identify the portion of the race that has uniform acceleration, and how you would calculate the uniform acceleration.

(c) After collecting data on your runner, you observe the first 10 meters of a 100-meter dash are covered in 2 seconds by a sprinter who starts from rest and accelerates with a constant acceleration. The remaining 90 meters are run with the same velocity the sprinter had after 2 seconds. i. Determine the sprinter's constant acceleration during the first 2 seconds.

ii. Determine the sprinters velocity after 2 seconds have elapsed.

iii. Determine the total time needed to run the full 100 meters

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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2. (12 points) The figure below represents a racetrack with semicircular sections connected by straight sections. Each section has length d, and markers along the track are spaced d/4 apart. Two people drive cars counterclockwise around the track, as shown. Car X goes around the curves at constant speed vc, increases speed at constant acceleration for half of each straight section to reach a maximum speed of 2vc, then brakes at constant acceleration for the other half of each straight section to return to speed vc. Car Y also goes around the curves at constant speed vc, increases speed at constant acceleration for one-fourth of each straight section to reach the same maximum speed 2vc, stays at that speed for half of each straight section, then brakes at constant acceleration for the remaining fourth of each straight section to return to speed vc. (a) On the figures below, draw an arrow showing the direction of the net force on each of the cars at the positions noted by the dots. If the net force is zero at any position, label the dot with 0.

(b) i. Indicate which car, if either, completes one trip around the track in less time, and justify your answer qualitatively without using equations.

ii.

Justify your answer about which car, if either, completes one trip around the track in less time quantitatively with appropriate equations.

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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2000B1  AP 1 A 0.50 kg cart moves on a straight horizontal track. The graph of velocity v versus time t for the cart is given below.

a. At which moments and/or intervals is the cart at rest?

b. On the axes below, plot the acceleration a versus time t graph for the motion of the cart from t = 0 to t = 25 s.

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c. A group of students are discussing the conditions in which acceleration is positive vs negative. A student claims that acceleration is negative when an object is slowing down because acceleration always has the same sign as Δv. i) What part of the student’s argument (if any) is correct?

ii)

What part of the student’s argument (if any) is incorrect?

iii)

Chose one motion interval from the graphs above that is consistent with the student’s argument and identify the supporting features.

iv)

Chose one motion interval from the graphs above that contradicts the student’s argument and identify the contradicting features.

AP Physics 1 Week 1 Practice MC Kinematics, Momentum, Center of Mass

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