- 1 -APPH_MidTerm. Mid - Term Exam. Part 1: Write your answers to all multiple choice questions in this space. A B C D E A B C D E

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1 Name - 1 -APPH_MidTerm AP Physics Date Mid - Term Exam Part 1: Write your answers to all multiple choice questions in this space. 1) 2) 3) 10) 11) 19) 20) 4) 12) 21) 5) 13) 22) 6) 7) 14) 15) 23) 24) 8) 16) 25) 9) 17) 26) 18) 27) Scrap work space

2 - 2 -APPH_MidTerm Part 2: Write your answers to the free response questions in the space below 1.

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5 - 5 -APPH_MidTerm 1. From the top of a high cliff, a ball is thrown horizontally with initial speed v o. Which of the following graphs best represents the ball's kinetic energy K as a function of time t? 2. A 5-meter uniform plank of mass 100 kilograms rests on the top of a building with 2 meters extended over the edge as shown above. How far can a 50-kilogram person venture past the edge of the building on the plank before the plank just begins to tip? (A) 0.5 m (B) 1 m (C) 1.5 m (D) 2 m (E) It is impossible to make the plank tip since the person would have to be more than 2 meters from the edge of the building. 3. A person weighing 800 newtons on Earth travels to another planet with twice the mass and twice the radius of Earth. The person's weight on this other planet is most nearly (A) 400 N (B) 800 N 2 (C) 800 N (D) N (E) 1,600 N 4. A racing car is moving around the circular track of radius 300 meters shown above. At the instant when the car's velocity is directed due east, its acceleration is directed due south and has a magnitude of 3 meters per second squared. When viewed from above, the car is moving (A) clockwise at 30 m/s (B) clockwise at 10 m/ s (C) counterclockwise at 30 m/ s (D) counterclockwise at 10 m/s (E) with constant velocity

6 - 6 -APPH_MidTerm 5. A block of weight W is pulled along a horizontal surface at constant speed v by a force F, which acts at an angle of with the horizontal, as shown above. The normal force exerted on the block by the surface has magnitude (A) W - F cos (B) W-Fsin (C) W (D) W + Fsin (E) W + Fcos 6. A horizontal force F is used to pull a 5-kilogram block across a floor at a constant speed of 3 meters per second. The frictional force between the block and the floor is 10 newtons. The work done by the force F in 1 minute is most nearly (A) 0 J (B) 30 J (C) 600 J (D) 1,350 J (E) 1,800 J Questions 7 & 8 A ball swings freely back and forth in an arc from point I to point IV, as shown above. Point II is the lowest point in the path, III is located 0.5 meter above II, and IV is I meter above II. Air resistance is negligible. 7. If the potential energy is zero at point II, where will the kinetic and potential energies of the ball be equal? (A) At point II (B) At some point between II and III (C) At point III (D) At some point between III and IV (E) At point IV 8. The speed of the ball at point II is most nearly (A) 3.0 m/s (B) 4.5 m/s (C) 9.8 m/s (D) 14 m/s (E) 20 m/s

7 - 7 -APPH_MidTerm 9. When an object of weight W is suspended from the center of a massless string as shown above. the tension at any point in the string is (A) 2Wcos (B) ½Wcos (C) Wcos (D) (E) W 2cos W cos 10. A projectile is fired with initial velocity v o at an angle with the horizontal and follows the trajectory shown above. Which of the following pairs of graphs best represents the vertical components of the velocity and acceleration. v and a, respectively, of the projectile as functions of time t? 11. In which of the following situations would an object be accelerated? I. It moves in a straight line at constant speed. II. It moves with uniform circular motion. III. It travels as a projectile in a gravitational field with negligible air resistance. (A) I only (B) III only (C) I and II only (D) II and III only (E) I, II, and III.

8 - 8 -APPH_MidTerm 12. An ideal spring obeys Hooke's law, F = -kx. A mass of 0.50 kilogram hung vertically from this spring stretches the spring meter. The value of the force constant for the spring is most nearly (A) 0.33 N/m (B) 0.66 N/m (C) 6.6 N/m (D) 33 N/m (E) 66 N/m 13. 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. If the masses of the cord and the pulley are negligible, what is the magnitude of the acceleration of the descending block? (A) Zero (B) g/4 (C) g/3 (D) 2g/3 (E) g 14. A solid metal ball and a hollow plastic ball of the same external radius are released from rest in a large vacuum chamber. When each has fallen 1m, they both have the same (A) inertia (B) speed (C) momentum (D) kinetic energy (E) change in potential energy 15. Units of power include which of the following? I. Watt II. Joule per second III. Kilowatt-hour (A) I only (B) III only (C) I and II only (D) II and III only (E) I, II, and III 16. A 2 kg object moves in a circle of radius 4 m at a constant speed of 3 m/s. A net force of 4.5 N acts on the object. What is the angular momentum of the object with respect to an axis perpendicular to the circle and through its center? (A) 9 N m/kg (B) 12 m 2 /s (C) 13.5 kg m 2 /s 2 (D) 18 N m/kg (E) 24 kg m 2 /s. 17. Two objects of mass 0.2 kg and 0.1 kg, respectively, move parallel to the x-axis, as shown above. The 0.2 kg object overtakes and collides with the 0.1 kg object. Immediately after the collision, the y-component of the velocity of the 0.2 kg object is 1 m/s upward. What is the y-component of the velocity of the 0.1 kg object immediately after the collision'? (A) 2 m/s downward (B) 0.5 m/s downward (C) 0 m/s (D) 0.5 m/s upward (E) 2 m/s upward

9 Question APPH_MidTerm 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. 18. The sum of the forces on the object is zero 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 19. A ball of mass 0.4 kg is initially at rest on the ground. It is kicked and leaves the kicker's foot with a speed of 5.0 m/s in a direction 60 above the horizontal. The magnitude of the impulse imparted by the ball to the foot is most nearly 2 (A) 1 N s (B) 3 N s (C) 2 N s (D) 3 N s (E) 4 N s Questions 20 & 21 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 v How much time does it take the rock to travel from the edge of the building to the ground? (A) hv o (B) h v 0 hv 0 (C) g (D) 2h g (E) 2h g 21. What is the kinetic energy of the rock just before it hits the ground? (A) mgh (B) ½ mv 0 2 (C) ½ mv mgh (D) ½ mv 0 2 +mgh (E) mgh-½ mv 0 2 Questions 22 & 23 A thermodynamic system is taken from an initial state X along the path XYZX as shown in the PV-diagram above. 22. For the process X Y, U is greater than zero and (A) Q<0 and W = 0 (B) Q<0 and W>0 (C) Q>0 and W<0 (D) Q>0 and W=0 (E) Q>0 and W>0 23. For the process Y Z, Q is greater than zero and (A) W<0 and U=0 (B) W=0 and U<0 (C) W=0 and U>0 ( D) W >0 and U=0 (E) W>0 and U>0

10 - 10 -APPH_MidTerm 24. An ideal gas confined in a box initially has pressure p. If the absolute temperature of the gas is doubled and the volume of the box is quadrupled, the pressure is (A) p/8 (B) p/4 (C) p/2 (D) p (E) 2p Questions 25 & 26 A certain quantity of an ideal gas initially at temperature T, pressure p 0, and volume V 0 is compressed to one-half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3). 25. Which of the following is true of the mechanical work done on the gas? (A) It is greatest for process 1. (B) It is greatest for process 3. (C) It is the same for processes I and 2 and less for process 3. (D) It is the same for processes 2 and 3 and less for process 1. (E) It is the same for all three processes. 26. Which of the following is true of the final temperature of this gas? (A) It is greatest for process 1. (B) It is greatest for process 2. (C) It is greatest for process 3. (D) It is the same for processes 1 and 2. (E) It is the same for processes 1 and In a certain process, 400 J of heat is added to a system and the system simultaneously does 100 J of work. The change in internal energy of the system is (A) 500 J (B) 400 J (C) 300 J (D) -100 J (E) -300 J

11 - 11 -APPH_MidTerm Part II: Constructed Response Questions: Show all work for answers to this part on the answer sheets provided. 1. A coin C of mass kg is placed on a horizontal disk at a distance of 0.14 m from the center, as shown above. The disk rotates at a constant rate in a counterclockwise direction as seen from above. The coin does not slip, and the time it takes for the coin to make a complete revolution is 1.5 s. a. The figure below shows the disk and coin as viewed from above. Draw and label vectors on the figure below to show the instantaneous acceleration and linear velocity vectors for the coin when it is at the position shown. b. Determine the linear speed of the coin. c. The rate of rotation of the disk is gradually increased. The coefficient of static friction between the coin and the disk is Determine the linear speed of the coin when it just begins to slip. d. If the experiment in part (c) were repeated with a second, identical coin glued to the top of the first coin, how would this affect the answer to part (c)? Explain your reasoning.

12 APPH_MidTerm A cylinder is fitted with a freely moveable piston of area 1.20 x 10-2 m 2 and negligible mass. The cylinder below the piston is filled with a gas. At state 1, the gas has volume 1.50 x 10-3 m 3, pressure 1.02 x 10 5 Pa, and the cylinder is in contact with a water bath at a temperature of 0 C. The gas is then taken through the following four-step process. A 2.50 kg metal block is placed on top of the piston, compressing the gas to state 2, with the gas still at 0 C. The cylinder is then brought in contact with a boiling water bath, raising the gas temperature to 100 C at state 3. The metal block is removed and the gas expands to state 4 still at 100 C. Finally, the cylinder is again placed in contact with the water bath at 0 C, returning the system to state 1. a. Determine the pressure of the gas in state 2. b. Determine the volume of the gas in state 2. c. Indicate below whether the process from state 2 to state 3 is isothermal, isobaric, or adiabatic. Isothermal Isobaric Adiabatic Explain your reasoning. d. Is the process from state 4 to state 1 isobaric? Yes No Explain your reasoning. e. Determine the volume of the gas in state 4.

13 APPH_MidTerm An airplane accelerates uniformly from rest. A physicist passenger holds up a thin string of negligible mass to which she has tied her ring, which has a mass m. She notices that as the plane accelerates down the runway, the string makes an angle with the vertical as shown above. a. In the space below, draw a free-body diagram of the ring, showing and labeling all the forces present. The plane reaches a takeoff speed of 65 m/s after accelerating for a total of 30 s. b. Determine the minimum length of the runway needed. c. Determine the angle that the string makes with the vertical during the acceleration of the plane before it leaves the ground. d. What additional information would be needed in order to estimate the mechanical energy of the airplane at the instant of takeoff? Explain your answer.