AP Physics 1 Chapter 5

28) The figure shows an object's acceleration-versus-force graph. What is the mass of this object? A) 2.5 g B) 1.6 g C) 630 g D) 400,000 g

A

29) The figure shows an acceleration-versus-force graph for three objects pulled by wires. If the mass of object 2 is 36 kg, what are the masses of objects 1 and 3? A) 12 kg and 90 kg B) 72 kg and 18 kg C) 90 kg and 12 kg D) 12 kg and 72 kg

A

32) A 1000-kg barge is being towed by means of two horizontal cables. One cable is pulling with a force of 80.0 N in a direction 30.0° west of north. In what direction should the second cable pull so that the barge will accelerate northward, if the force exerted by the cable is 120 N? Assume that the water exerts no appreciable frictional drag on the barge. A) 19.5° east of north B) 21.1° east of north C) 39.0° east of north D) 47.5° east of north E) 54.7° east of north

A

33) Two forces act on a object. One force has magnitude 65 N directed 59° clockwise from the positive x-axis, and the other has a magnitude 35 N at 32° clockwise from the positive y-axis. What is the magnitude of this object's acceleration? A) 1.1 m/s2 B) 1.3 m/s2 C) 1.5 m/s2 D) 1.7 m/s2

A

34) A tightrope walker walks across a 30-m long wire tied between two poles. The center of the wire is displaced vertically downward by 1.0 m when he is halfway across. If the tension in both halves of the wire at this point is what is the mass of the tightrope walker? Neglect the mass of the wire. A) 85 kg B) 43 kg C) 74 kg D) 91 kg

A

39) A 6.00-kg ornament is held at rest by two light wires that form 30° angles with the vertical, as shown in the figure. An external force of magnitude F acts vertically downward on the ornament. The tension exerted by each of the two wires is denoted by T. A free-body diagram, showing the four forces that act on the box, is shown in the figure. If the magnitude of force F is 410 N, what is the magnitude of the tension T? A) 271 N B) 235 N C) 188 N D) 376 N E) 470 N

A

40) The figure shows a block of mass M hanging at rest. The light wire fastened to the wall is horizontal and has a tension of 38 N. The wire fastened to the ceiling is also very light, has a tension of and makes an angle θ with the ceiling. Find the angle θ. A) 50° B) 40° C) 33° D) 65° E) 45°

A

83) A slanted roof rises at 35° above the horizontal, and the straight-line distance from the top of the roof to the bottom edge is 4.5 m. The roof is covered with ice, so it offers no friction to objects sliding on it. A piece of ice at the top suddenly breaks loose and begins to slide down from rest. (a) How long will it take for the ice to reach the bottom edge of the roof? (b) How fast will the ice be traveling just as it reaches the bottom edge?

(a) 1.3 s (b) 7.1 m/s

88) A 5.0-kg box slides on the surface on a ramp that rises at 37° above the horizontal. The coefficient of kinetic friction between the box and the surface of the ramp is 0.60. What are the magnitude and direction of the acceleration of the box if it is sliding (a) up the ramp, (b) down the ramp?

(a) 11 m/s2 down the ramp (b) 1.2 m/s2 down the ramp

23) A 958-N rocket is coming in for a vertical landing. It starts with a downward speed of 25 m/s and must reduce its speed to 0 m/s in 8.0 s for the final landing. (a) During this landing maneuver, what must be the thrust due to the rocket's engines? (b) What must be the direction of the engine thrust force?

(a) 1300 N (b) upward

57) Three blocks, light connecting ropes, and a light frictionless pulley comprise a system, as shown in the figure. An external force of magnitude P is applied downward on block A, causing block A to accelerate downward at a constant 2.5 m/s2. The tension in the rope connecting block B and block C is equal to 60 N. (a) What is the magnitude of the force P? (b) What is the mass of block C?

(a) 190 N (b) 4.9 kg

85) A system consisting of blocks, a light frictionless pulley, a frictionless incline, and very light connecting wires is shown in the figure. The wires pull on the left-hand blocks parallel to the surface of the ramp. The 9.0-kg block accelerates downward when the system is released gently from rest. (a) What is the magnitude of the acceleration of the 9.0-kg block? (b) What is the tension in the wire connecting the two blocks on the incline?

(a) 2.1 m/s2 (b) 42 N

44) Three objects are connected by weightless flexible strings as shown in the figure. The pulley has no appreciable mass or friction, and the string connected to the block on the horizontal bench pulls on it parallel to the bench surface. The coefficients of friction between the bench and the block on it are µs = 0.66 and µk = 0.325. You observe that this system remains at rest. (a) Find the mass of the hanging object A. (b) What is the magnitude of the friction force on the block on the bench?

(a) 22 kg (b) 270 N

79) The figure shows a system consisting of three blocks, a light frictionless pulley, and light connecting ropes that act horizontally on the upper two blocks. The 9.0-kg block is on a perfectly smooth horizontal table. The surfaces of the 12-kg block are rough, with µk = 0.30 between the 12-kg and 9.0-kg blocks. The mass M of the hanging block is set so that it descends at a constant velocity of 3.25 m/s. (a) What is the mass M of the hanging block? (b) The mass M is now changed to 5.0 kg, causing it to accelerate downward after it is released. What is the acceleration of the hanging mass?

(a) 3.6 kg (b) 0.98 m/s2

9) A 40-kg crate is being lowered with a downward acceleration is 2.0 m/s2 by means of a rope. (a) What is the magnitude of the force exerted by the rope on the crate? (b) What would be the magnitude of the force exerted by the rope if the crate were being raised with an acceleration of 2.0 m/s2?

(a) 310 N (b) 470 N

37) An object is being acted upon by three forces and moves with a constant velocity. One force is 60 N along the +x-axis, the second is 75 N along a direction making a counterclockwise angle of 150° with the +x-axis. (a) What is the magnitude of the third force? (b) What is the direction of the third force, measured clockwise from the +x-axis?

(a) 38 N (b) 260°

50) As shown in the figure, two blocks are connected by a very light string, and the upper block is pulled upward by a different string. The masses of the upper and lower blocks are 300 g and 240 g, respectively. The string between the blocks will break if its tension exceeds 3.6 N, and the string that pulls the combination upward will break if its tension exceeds 7.8 N. (a) What is the largest upward acceleration that the blocks can be given without either string breaking? (b) If the upward acceleration is slightly higher than this, which string breaks, the upper one or the lower one?

(a) 4.6 m/s2 (b) upper string

41) A very light wire is used to hang a series of 8.0-kg bricks. This wire will break if the tension in it exceeds 450 N. The bricks are hung one below the other from a hook in the ceiling using this wire, as shown in the figure. (a) How many whole bricks can be hung without breaking the wire? (b) If you add one more brick to the number found in part (a), which string will break?

(a) 5 (b) the top wire

82) A 2.8-kg tool can move on a perfectly smooth ramp that slants at 42° above the horizontal. What are the magnitude and direction of the acceleration of this tool if it is sliding (a) up the ram, (b) down the ramp?

(a) 6.6 m/s2 down the ramp (b) 6.6 m/s2 down the ramp

59) A locomotive is pulling three train cars along a level track with a force of 100,000 N. The car next to the locomotive has a mass of 80,000 kg, the next one, 50,000 kg, and the last one, 70,000 kg. You can neglect the friction on the cars being pulled. (a) What is the magnitude of the force between that the 80,000-kg car exerts on the 50,000-kg car? (b) What is the magnitude of the force that the 50,000-kg car exerts on the 70,000-kg car?

(a) 60,000 N (b) 35,000 N

78) You push horizontally on a 120-N box that is initially resting on a horizontal table. The coefficient of static friction between the box and the table is 0.75, and the coefficient of kinetic friction is 0.40. Find the friction force on the box if the push is equal to (a) 84 N; (b) 94 N.

(a) 84 N (b) 48 N

52) A 5.0-kg block and a 4.0-kg block are connected by a 0.6 kg rod, as shown in the figure. The links between the blocks and the rod are denoted by A and B. A vertical upward force of magnitude F is applied to the upper block. The blocks and rod assembly are moving downward at constant velocity of 85 cm/s. (a) What is the magnitude of the applied force F? (b) What magnitude force does link A exert?

(a) 94 N (b) 45 N

80) As shown in the figure, block B on a horizontal tabletop is attached by very light horizontal strings to two hanging blocks, A and C. The pulleys are ideal, and the coefficient of kinetic friction between block B and the tabletop is 0.100. The masses of the three blocks are mA = 12.0 kg, mB = 7.00 kg, and mC = 10.0 kg. Find the magnitude and direction of the acceleration of block B after the system is gently released and has begun to move.

0.44 m/s2, to the left

22) A 590-kg rocket is at rest on the launch pad. What upward thrust force is needed to accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

1.1 × 104 N

18) In a certain particle accelerator, a proton reaches an acceleration of 9.0 × 1013 m/s2. The mass of a proton is 1.67 × 10-27 kg. What is the force on the proton?

1.5 × 10-13 N

35) A 30.0-kg load is being held in place using massless wires in the ideal pulley arrangement shown in the figure. What is the magnitude of the force F?

147 N

21) A box of mass 72 kg is at rest on a horizontal frictionless surface. A constant horizontal force of magnitude F then acts on the box, accelerating it to the right. You observe that it takes the box 3.4 seconds to travel 13 meters. What is the magnitude of the force F?

160 N

61) A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30, and the coefficient of kinetic friction is 0.20. What horizontal force must be applied to the box to cause it to start sliding along the surface?

160 N

92) A 200-g hockey puck is launched up a ramp that is inclined at a 30° angle above the horizontal. The coefficients of static and kinetic friction between the puck and the ramp are µs = 0.40 and µk = 0.30, respectively, and the puck's initial velocity at the base is 3.8 m/s parallel to the sloping surface of the ramp. What speed does the puck have when it slides back down to its starting point?

2.1 m/s

25) A 10-kg object is hanging by a very light wire in an elevator that is traveling upward. The tension in the rope is measured to be 75 N. What are the magnitude and direction of the acceleration of the elevator?

2.3m/s2, downward

93) Two packages are connected by a very light string that goes over an ideal pulley as shown in the figure. Package A has a mass of 3.0 kg and can slide along a rough plane inclined at 30° above the horizontal. The string acts on package A parallel to the surface of the plane. The coefficient of static friction between package A and the plane is 0.40. What minimum mass should package B have in order to start package A sliding up the ramp?

2.5 kg

51) A locomotive is pulling 9 freight cars, each of which is loaded with the same weight. The mass of each loaded car is and we can neglect friction on these 9 cars. If the train is accelerating forward at on a level track, what is the tension in the coupling between the second and third cars? (The car nearest the locomotive is counted as the first car.)

210,000 N

64) A bulldozer attempts to drag a log weighing 500 N along the rough horizontal ground. The cable attached to the log makes an angle of 30° above the ground. The coefficient of static friction between the log and the ground is 0.50, and the coefficient of kinetic friction is 0.35. What minimum tension is required in the cable in order for the log to begin to slide?

220 N

20) A flatbed truck is carrying an 800-kg load of timber that is not tied down. The maximum friction force between the truck bed and the load is 2400 N. What is the greatest acceleration that the truck can have without losing its load?

3.0 m/s2

19) During a hard stop, a car and its passengers slow down with an acceleration of 8.0 m/s2. What magnitude force does a 50-kg passenger exert on the seat belt in such a stop?

400 N

86) A 150-N crate is being pulled up a perfectly smooth ramp that slopes upward at 15° by a pull that is directed at 30° above the surface of the ramp. What is the magnitude of the pull required to make the crate move up the ramp at a constant velocity of 1.75 m/s?

45 N

87) A 7.5-kg stone moves up frictionless hill that slopes upward at 41° above the horizontal. If the stone has an initial velocity of 8.5 m/s at the bottom, how far (as measured along the surface of the hill) will it go before stopping?

5.6 m

27) The figure shows an acceleration-versus-force graph for a 125-g object. What should be the value of the first tick-mark on the vertical scale, as indicated by the arrow in the figure? A) 4 B) 8 C) 0.00400 D) 0.00800

A

15) A catcher stops a 0.15-kg ball traveling at 40 m/s in a distance of 20 cm. What is the magnitude of the average force that the ball exerts against his glove?

600 N

53) A 5.0-kg block and a 4.0-kg block are connected by a 0.6 kg rod, as shown in the figure. The links between the blocks and the rod are denoted by A and B. A vertical upward force of magnitude F of magnitude 150 N is applied to the upper block. What magnitude force does each of the links A and B exert?

72 N (link A), 63 N (link B)

1) What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g = 9.80 m/s2? A) 69.9 kg B) 68.5 kg C) 71.3 kg D) 72.7 kg

A

10) A 450-kg sports car accelerates from rest to 100 km/h in 4.80 s. What magnitude force does a 68.0 kg passenger experience during the acceleration? A) 394 N B) 82.0 N C) 342 N D) 311 N

A

12) A car of mass 1100 kg that is traveling at 27 m/s starts to slow down and comes to a complete stop in 578 m. What is the magnitude of the average braking force acting on the car? A) 690 N B) 550 N C) 410 N D) 340 N

A

2) If I weigh 741 N on Earth at a place where g = 9.80 m/s2 and 5320 N on the surface of another planet, what is the acceleration due to gravity on that planet? A) 70.4 m/s2 B) 51.4 m/s2 C) 61.2 m/s2 D) 81.0 m/s2

A

43) A 10.0-kg picture is held in place by two wires, the first one hanging at 50.0° to the left of the vertical and the second one at 45.0° to the right of the vertical. What is the tension in the first wire? A) 69.6 N B) 50.8 N C) 98.1 N D) 69.4 N E) 23.8 N

A

45) A load is being lifted vertically upwards by means of two cables attached to it. The first cable exerts a force of 600 N at an angle of 35.0° to the left of the vertical. The second cable exerts a force of 1300 N. At what angle to the right of the vertical is the second cable pulling? A) 15.4° B) 16.2° C) 30.8° D) 67.8° E) 75.8°

A

48) A 3.0-kg and a 5.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 5.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other? A) 12 N B) 20 N C) 24 N D) 32 N E) 0 N

A

56) As shown in the figure, a 10-kg block on a perfectly smooth horizontal table is connected by a horizontal string to a 63-kg block that is hanging over the edge of the table. What is the magnitude of the acceleration of the 10-kg block when the other block is gently released? A) 8.5 m/s2 B) 8.1 m/s2 C) 7.5 m/s2 D) 9.0 m/s2

A

58) The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes 0.53 s for it to reach the floor. What is the mass m of the block on the left? There is no friction or mass in the pulley, and the connecting rope is very light. A) 16 kg B) 14 kg C) 13 kg D) 11 kg

A

63) An object slides on a level floor. It slows and comes to a stop with a constant acceleration of magnitude 2.4 m/s2. What is the coefficient of kinetic friction between the object and the floor? A) 0.24 B) 0.48 C) 0.12 D) It is impossible to determine without knowing the mass of the object.

A

69) A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30. A horizontal 140-N force is applied to the box. What is the friction force on the box? A) 140 N B) 160 N C) 16.5 N D) 0.00 N E) 42 N

A

7) A block is on a frictionless table, on earth. The block accelerates at 3.0 m/ when a horizontal force is applied to it. The block and table are set up on the Moon where the acceleration due to gravity is 1.62 m/ . The weight of the block on the Moon is closest to A) 11 N. B) 9.5 N. C) 8.1 N. D) 6.8 N. E) 5.5 N.

A

70) A horizontal 52-N force is needed to slide a box across a flat surface at a constant velocity of 3.5 m/s. What is the coefficient of kinetic friction between the box and the floor? A) 0.11 B) 0.09 C) 0.10 D) 0.13

A

71) In a shuffleboard game, the puck slides a total of 12 m on a horizontal surface before coming to rest. If the coefficient of kinetic friction between the puck and board is 0.10, what was the initial speed of the puck? A) 4.8 m/s B) 48.5 m/s C) 3.8 m/s D) 4.3 m/s

A

73) A driver in a car traveling at slams on the brakes and skids to a stop. If the coefficient of friction between the tires and the level road is 0.80, how long will the skid marks be? A) 37 m B) 30 m C) 46 m D) 34 m

A

74) A flatbed truck is carrying a 20.0-kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400, and the coefficient of kinetic friction is 0.300. What is the maximum acceleration that the truck can have if the crate is to stay in place relative to the truck? A) 3.92 m/s2 B) 7.84 m/s2 C) 8.00 m/s2 D) 78.5 m/s2 E) 196 m/s2

A

75) You push downward on a trunk at an angle 25° below the horizontal with a force of If the trunk is on a flat surface and the coefficient of static friction between the surface and the trunk is 0.61, what is the most massive trunk you will be able to move? A) 81 kg B) 93 kg C) 73 kg D) 112 kg

A

76) Jason takes off across level water on his jet-powered skis. The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible). The skis produce a forward thrust of 200 N and have a coefficient of kinetic friction with water of 0.10. Unfortunately, the skis run out of fuel after only 90 s. What is Jason's top speed? A) 150 m/s B) 240 m/s C) 24 m/s D) 90 m/s

A

77) Jason takes off across level water on his jet-powered skis. The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible). The skis produce a forward thrust of 200 N and have a coefficient of kinetic friction with water of 0.10. Unfortunately, the skis run out of fuel after only 41 s. How far from his starting point has Jason traveled when he finally coasts to a stop? A) 3900 m B) 2900 m C) 2000 m D) 1400 m

A

8) A block is on a frictionless table, on earth. The block accelerates at 5.3 m/ when a horizontal force is applied to it. The block and table are set up on the Moon where the acceleration due to gravity is 1.62 m/ . A horizontal force of 5 N is now applied to the block when it is on the Moon. The acceleration imparted to the block by this force is closest to A) 2.7 m/ . B) 2.4 m/ . C) 2.9 m/ . D) 3.2 m/ . E) 3.4 m/ .

A

84) A 15-kg block is on a frictionless ramp that is inclined at 20° above the horizontal. It is connected by a very light string over an ideal pulley at the top edge of the ramp to a hanging 19-kg block, as shown in the figure. The string pulls on the 15-kg block parallel to the surface of the ramp. Find the magnitude of the acceleration of the 19-kg block after the system is gently released? A) 4.0 m/s2 B) 3.8 m/s2 C) 4.2 m/s2 D) 4.5 m/s2

A

89) A 6.0-kg box slides down an inclined plane that makes an angle of 39° with the horizontal. If the coefficient of kinetic friction is 0.40, at what rate does the box accelerate down the slope? A) 3.1 m/s2 B) 3.4 m/s2 C) 3.7 m/s2 D) 4.1 m/s2

A

90) A 200-g hockey puck is launched at an initial speed of 16 m/s up a metal ramp that is inclined at a 30° angle. The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µs = 0.40 and µk = 0.30, respectively. What vertical height does the puck reach above its starting point? A) 8.6 cm B) 17 cm C) 13 cm D) 4.2 cm

A

47) A 3.0-kg and a 5.0-kg box rest side-by-side on a perfectly smooth, level floor. A horizontal force of 32 N is applied to the 3.0-kg box pushing it against the 5.0-kg box, and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other? A) 12 N B) 20 N C) 24 N D) 32 N E) 0 N

B

91) The figure shows a block of mass m resting on a 20° slope. The block has coefficients of friction and with the surface of the slope. It is connected using a very light string over an ideal pulley to a hanging block of mass 2.0 kg. The string above the slope pulls parallel to the surface. What is the minimum mass m so the system will remain at rest when it is released from rest? A) 2.1 kg B) 3.3 kg C) 1.3 kg D) 3.6 kg

A

13) A certain aircraft has a mass of 300,000 kg. At a certain instant during its landing, its speed is 27.0 m/s. If the braking force is a constant 445,000 N, what is the speed of the airplane 10.0 s later? A) 10.0 m/s B) 12.2 m/s C) 14.0 m/s D) 18.0 m/s E) 20.0 m/s

B

24) Calculate the average force a bumper would have to exert to bring a 1200-kg car to rest in 15 cm when the car had an initial speed of 2.0 m/s (about 4.5 mph). A) 1.8 × 104 N B) 1.6 × 104 N C) 5.4 × 104 N D) 6.5 × 105 N E) 3.2 × 104 N

B

30) A 50.0-kg crate is being pulled along a horizontal smooth surface. The pulling force is 10.0 N and is directed 20.0° above the horizontal. What is the magnitude of the acceleration of the crate? A) 0.0684 m/s2 B) 0.188 m/s2 C) 0.200 m/s2 D) 0.376 m/s2 E) 0.0728 m/s2

B

31) A 40-kg box is being pushed along a horizontal smooth surface. The pushing force is 15 N directed at an angle of 15° below the horizontal. What is the magnitude of the acceleration of the crate? A) 0.16 m/s2 B) 0.36 m/s2 C) 0.47 m/s2 D) 0.39 m/s2 E) 0.68 m/s2

B

6) If a net force accelerates a 4.5-kg tool at 40 m/s2, what acceleration would that same net force give to an 18-kg tool? A) 180 m/s2 B) 10 m/s2 C) 160 m/s2 D) 9.8 m/s2 E) 32 m/s2

B

62) The coefficients of static and kinetic friction between a 3.0-kg box and a horizontal desktop are 0.40 and 0.30, respectively. What is the force of friction on the box when a 15-N horizontal push is applied to the box? A) 12 N B) 8.8 N C) 15 N D) 6.0 N E) 4.5 N

B

65) A policeman investigating an accident measures the skid marks left by a car on the horizontal road. He determines that the distance between the point that the driver slammed on the brakes (thereby locking the wheels) and the point where the car came to a stop was 28.0 m. From a reference manual he determines that the coefficient of kinetic friction between the tires and the road under the prevailing conditions was 0.300. How fast was the car going when the driver applied the brakes? A) 10.7 m/s B) 12.8 m/s C) 21.4 m/s D) 32.9 m/s E) 45.7 m/s

B

68) A baseball player is running to second base at 5.03 m/s. When he is 4.80 m from the plate he goes into a slide. The coefficient of kinetic friction between the player and the ground is 0.180, and the coefficient of static friction is 3.14. What is his speed when he reaches the plate? A) 4.47 m/s B) 2.89 m/s C) 1.96 m/s D) 2.56 m/s E) He stops before reaching the plate.

B

72) During a hockey game, a puck is given an initial speed of 10 m/s. It slides 50 m on the horizontal ice before it stops due to friction. What is the coefficient of kinetic friction between the puck and the ice? A) 0.090 B) 0.10 C) 0.11 D) 0.12

B

14) What magnitude net force is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s? A) 444 N B) 1620 N C) 3240 N D) 4360 N E) 11800 N

C

16) An object that weighs 75 N is pulled on a horizontal surface by a horizontal pull of 50 N to the right. The friction force on this object is 30 N to the left. What is the acceleration of the object? A) 0.27 m/s2 B) 1.1 m/s2 C) 2.6 m/s2 D) 11 m/s2

C

17) A 1200-kg car is pulling a 500-kg trailer along level ground. Friction of the road on the trailer is negligible. The car accelerates with an acceleration of 1.3 m/s2. What is the force exerted by the car on the trailer? A) 550 N B) 600 N C) 650 N D) 700 N E) 750 N

C

38) A piano mover raises a 1000-N piano at a constant speed using a very light rope in a frictionless pulley system, as shown in the figure. With what force is the mover pulling down on the rope? A) 2000 N B) 1000 N C) 500 N D) 250 N E) Depends on the speed of the piano.

C

49) Three boxes rest side-by-side on a smooth, horizontal floor. Their masses are 5.0 kg, 3.0 kg, and 2.0 kg, with the 3.0-kg mass in the center. A force of 50 N pushes on the 5.0-kg box, which pushes against the other two boxes. What magnitude force does the 5.0-kg box exert on the 3.0-kg box? A) 0 N B) 10 N C) 25 N D) 40 N E) 50 N

C

54) A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a very light rope that goes over an ideal pulley. If the masses are gently released, what is the resulting acceleration of the masses? A) 0.00 m/s2 B) 3.7 m/s2 C) 2.5 m/s2 D) 4.9 m/s2 E) 6.1 m/s2

C

60) In the figure, block A has a mass of 3.00 kg. It rests on a smooth horizontal table and is connected by a very light horizontal string over an ideal pulley to block B, which has a mass of 2.00 kg. When block B is gently released from rest, how long does it take block B to travel 80.0 cm? A) 0.404 s B) 0.494 s C) 0.639 s D) 0.785 s E) 0.935 s

C

67) A 50-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 30.0° below the horizontal is applied to the box. The coefficient of static friction between the box and the surface is 0.40, and the coefficient of kinetic friction is 0.30. What is the force of friction on the box? A) 32 N B) 200 N C) 220 N D) 250 N E) 620 N

C

94) A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N that is parallel to the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block? A) 0.528 m/ B) 0.158 m/ C) 0.412 m/ D) 0.983 m/ E) 0.260 m/

C

11) On its own, a tow truck has a maximum acceleration of 3.0 m/s2. What will be its maximum acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass? A) 2.5 m/s2 B) 2.0 m/s2 C) 1.5 m/s2 D) 1.0 m/s2

D

3) An astronaut weighs 99 N on the Moon, where the acceleration of gravity is 1.62 m/s2. How much does she weigh on Earth? A) 16 N B) 61 N C) 99 N D) 600 N E) 440 N

D

42) A 400-kg box is lifted vertically upward with constant velocity by means of two cables pulling at 40.0° on either side of the vertical direction. What is the tension in each cable? A) 231 N B) 400 N C) 800 N D) 2560 N E) 3920 N

D

46) A 10-kg sign is held by two ropes as shown in the figure. What is the tension on rope A? A) 44 N B) 69 N C) 72 N D) 88 N E) 98 N

D

66) A 50-kg box is being pushed along a horizontal surface. The coefficient of static friction between the box and the ground is 0.65, and the coefficient of kinetic friction is 0.35. What horizontal force must be exerted on the box for it to accelerate at 1.2 m/s2? A) 60 N B) 120 N C) 170 N D) 230 N E) 490 N

D

81) A flatbed truck is carrying a 20-kg crate up a sloping road. The coefficient of static friction between the crate and the bed is 0.40, and the coefficient of kinetic friction is 0.30. What is the maximum angle of slope that the truck can climb at constant speed if the crate is to stay in place? A) 0.38° B) 13° C) 17° D) 22° E) 68°

D

26) A 45.0-kg person steps on a scale in an elevator. The scale reads 460 N. What is the magnitude of the acceleration of the elevator? A) 4.91 m/s2 B) 9.81 m/s2 C) 46.9 m/s2 D) 0.206 m/s2 E) 0.422 m/s2

E

36) An object is being acted upon by three forces and as a result moves with a constant velocity. One force is 60.0 N along the +x-axis, and the second is 75.0 N along the +y-axis. What is the magnitude of the third force? A) 135 N B) 15.0 N C) 48.0 N D) 67.5 N E) 96.0 N

E

5) A net force of 125 N is applied to a certain object. As a result, the object accelerates with an acceleration of 24.0 m/s2. The mass of the object is A) 3000 kg. B) 2880 kg. C) 144 kg. D) 0.200 kg. E) 5.21 kg.

E

55) A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a rope that goes over an ideal pulley. If the masses are gently released from rest, how long does it take for the 3.0-kg mass to rise by 1.0 m? A) 0.41 s B) 0.74 s C) 0.82 s D) 1.8 s E) 0.90 s

E

4) An object has a mass of 60 kg on Earth. What are the mass and weight of this object on the surface of the Moon where the acceleration due to gravity is only 1/6 of what it is on Earth?

mass = 60 kg, weight = 98 N