nt schools - 1.how much work is done by friction if a 20 kg block … · 2019. 1. 24. · e) 840...

A) 84 joules B) 100 joulesC) 125 joules D) 200 joulesE) 840 joules

1. How much work is done by friction if a 20 kg blocksliding at 10 m/s is slowed down to 4m/s?

A) 0 joules B) 250 c joulesC) 250 c 2 joules D) 5,000 c joulesE) 50,000 c joules

2. How much work is done by a 2,000 kg rocket movingat a constant 0.5 c far from any source of gravitationalor electromagnetic force in 5 meters?


3. How much work is done lifting a 40 newton block 2meters?

A) 500 joules B) 700 joulesC) 1,000 joules D) 1,500 joulesE) 2,000 joules

4. How much work is done pushing a 10 kg box up africtionless 30 degree incline 5 meters high at aconstant rate?


5. A 30 newton box is being pushed at a constant rate.The coefficient of friction is 0.1 what is the workdone pushing the box 10 meters against friction?

A) 0 J B) 0.017 JC) 60 J D) 750 JE) 1500 J

6. In order to demonstrate some concepts of physics, aphysics teacher pushes against a wall with a force of300 N for 5 s. As you can imagine, the wall remainsstationary. How much work does the teacher do onthe wall in this time period?

A) 6 J B) 18 J C) 24 J D) 30 J E) 42 J

7. A student pulls a block 3.0 meters along a horizontalsurface at constant velocity. The diagram belowshows the components of the force exerted on theblock by the student.

How much work is done against friction?

A) 80 J B) 120 J C) 180 J D) 240 J E) 480 J

8. A horizontal force of 40 N is used to push a blockalong a horizontal surface at a constant speed of 2meters per second. How much work is done on theblock in 6 seconds?

A) WhB) Whg2C) Wh

gD) 2Wh

gE) 2Wh

9. How much work is done as a box of weight W isvertically lifted with an acceleration g, to a height h?

A) M/T2 B) ML/T2

C) ML2/T2 D) M/L2

E) T2/M

10. If L, M and T denote the dimensions of length, mass,and time, respectively, what are the dimensions ofenergy?

A) –10 J B) –5 J C) 0 J D) 5 J E) 10 J

11. A person lifts a box with a mass of 2.0 kg from theground to a shelf 0.5 m high. The work that gravitydoes on the box is equal to

A) 0 J B) 50 JC) 100 J D) 150 JE) 300 J

12. An object with a mass of 2 kg is attached to the endof a 3 m long string and is whirled horizontally in acircle with a constant speed of 5 m/s. When theobject has traveled half a revolution, how muchwork has been done by the centripetal force?

A) 0 J B) 24 JC) 1000 J D) 6000 JE) 12000 J

13. A vertical force of 500 N acts on a 12 kg mass over ahorizontal displacement of 2 m. The work done bythe force is

A) 25 J B) 50 JC) 86.67 J D) 14.4 JE) 35 J

14. A woman pushes a lawn mower with a force of F atan angle to the ground. If F = 20N and = 30°,what is the net work done in moving the lawnmower5m?

A) 0 J B) 16 J C) 32 J D) 8 J E) 4 J

15. A ball of mass 16 kg on the end of a string is spun ata constant speed of 2.0 m/s in a horizontal circlewith a radius of 1 m. What is the work done by thecentripetal force during one complete revolution?

A) MLFcos30B) LFcos30C) Lcos30D) Fcos30

MLE) MLcos30

F

16. A block of mass M is pulled by a constant force F atan angle of 30° relative to the ground for a distanceof L meters. What is the net work done?

A) Torque B) VelocityC) Work D) MomentumE) Force

17. Which of the following is not a vector quantity?

A) 25 meters B) 45 metersC) 90 meters D) 1,80 metersE) 250 meters

18. If a 5,000 kg runaway truck is traveling 30 m/s, howhigh must a ramp be to bring the truck to a completestop?

A) 5 newtons B) 10 newtonsC) 20 newtons D) 50 newtonsE) 100 newtons

19. A 1 kg radio controlled car is traveling at 10 m/s.When the car is 5 meters from a cliff the operatorhits the brakes. How much force is required to stopthe car?

A) 0.1 meters B) 0.6 metersC) 1 meter D) 2 metersE) 4 meters

20. Just before hitting a nail, a 2 kg hammer is movingat 10 m/s just before it hits a nail. If the wood exertsa constant 180 newton force on the nail, how fardoes the nail go?

A) 5 m/s B) 7 m/sC) 10 m/s D) 30 m/sE) 40 m/s

21. A 10 newton block sliding on a frictionless surfacegoes up a ramp 3 meters high. If the block is initiallytraveling at 10 m/s what is the final velocity of theblock?

A) 9 meters B) 18 metersC) 90 meters D) 180 metersE) 900 meters

22. If a 200 kg cart going 30 m/s brakes with a force of1,000 newtons how far will it travel before comingto a stop?

A) the force felt due to gravity is the same on bothmasses

B) their initial potential energies are equalC) they lose potential energy at the same rateD) they have the same kinetic energy upon hitting

the groundE) their accelerations are equal

23. Which of the following is true of a 1 kg mass and a 5kg mass that both fall from rest from the sameheight?

A) Gravitational Potential energy is converted intokinetic energy.

B) Elastic Potential Energy is converted intogravitational potential energy

C) Kinetic energy is converted into heat energy.D) Kinetic energy is converted into elastic

potential energy and heat.E) Kinetic energy is converted into gravitational

energy.

24. What happens to the energy of a bouncing ball as ithits the ground with a certain downward velocity?

A) F d – E B) (Fd – E)/dC) (F – E)/d D) FdE) E/d – F

25. If an object sliding on a rough surface experiencesan increase in kinetic energy of E while it is pushedby a constant force F through a distance d, what isthe force to due to friction?


26. A person does 100 joules of work in pulling back thestring of a bow. What will be the initial speed of a0.5-kilogram arrow when it is fired from the bow?

A) B)

C) D)

27. Which of the following graphs best represents thekinetic energy K of a particle as a function of themomentum p of the particle?


28. A 100 W motor propels an object with a mass of 4kg for 2 s from rest. Its final velocity will be

A) 16 J B) 64 J C) 128 J D) 256 J E) 512 J

29. An object with a mass of 2 kg increases in speedfrom 4 m/s to 12 m/s in 3 s. The total workperformed on the object during this time is

A) 1.0 × 102 JB) 5.0 × 102 JC) 2.0 × 104 JD) 1.0 × 105 JE) Cannot be determined from the information

provided.

30. A rail gun is able to accelerate a projectile with amass of 4 kg from rest to 100 m/s in 5 s. Calculatethe work done on the projectile by the force of therail gun.

A) M has one-fourth the kinetic energy of 2M.B) M has one-half the kinetic energy of 2M.C) M has the same amount of kinetic energy as

2M.D) M has twice the amount of kinetic energy as

2M.E) M has four times the amount of kinetic energy

as 2M.

31. Two balls of equal size are dropped from the sameheight from the roof of a building. One ball has massM and the other has a mass 2M. When the ballsreach the ground, how do the kinetic energies of thetwo balls compare? (Neglect friction)

A) 1,150 J B) 21,150 JC) 31,250 J D) 32,250 JE) 42,250 J

32. How much energy is required to stop a car of mass100 kg traveling at 25 m/s?

A) 0 J B) 20,000 JC) 4,000 J D) 8,000 JE) 16,000 J

33. A car with kinetic energy 20,000 J travels along ahorizontal road. How much work is required to stopthe car in 5 s?

A) m/s B) m/sC) m/s D) m/sE) m/s

34. An object at rest weighs 100 N on earth. It gains100 J of kinetic energy. What is its velocity?

Base your answers to questions 35 through 37 on thepicture below, which represents a plane 10 m inlength with a coefficient of kinetic friction of 0.2,inclined at an angle of 53º. A block of weight 30 Nis placed at the top of the plane and allowed to slidedown.

A) 10 J B) 12.0 JC) 18 J D) 24 JE) 36 J

35. The work done on the block by friction during its 10m slide down the plane is most nearly

A) 60 J B) 180 J C) 260 J D) 300 J E) 390 J

36. The work done on the block by the gravitationalforce during its 10 meter slide down the plane ismost nearly

A) 8.2 m/s B) 8.6 m/sC) 8.9 m/s D) 9.7 m/sE) 10.0 m/s

37. The velocity of the block after its 10 m slide downthe plane is most nearly

A) B)

C) D)

E)

38. A block of mass m moving with initial velocity v0 moves over a rough surface with coefficient ofkinetic friction ƒ. How long does it take for the blockto come to a complete stop?

A) B)

C) D)

E)

39. A particle is fired straight up out of a cannon.Which of the following graphs best represents itskinetic energy K as a function of time t?

Base your answers to questions 40 and 41 on the force vs. distance graph below, which is for anobject being pushed along a straight line, starting atrest.

A) 5 J B) 10 J C) 15 J D) 20 J E) 25 J

40. After the object has moved a distance of 2.0 m, howmuch work has been done on it?

A) 0.2 m/s B) 2.0 m/sC) 5.0 m/s D) 9.25 m/sE) 15 m/s

41. If the object has a mass of 1.4 kg, what is its velocityat 5.0 m?

A) 50 J B) 50 WC) 100 J D) 100 WE) 125 W

42. An object that starts at rest from the origin is pushedby a constant force of 10 N has a position given by x(t) = 5t2. What is the power delivered to the objectby the force at time t = 1 s?

A) F(t) = t 3 – 4tB) F(t) = t3C) F(t) = t 2/2 – 1D) F(t) = 3t 2 – 2E) More information is needed to determine the

force

43. If the power delivered to an object by a force actingon it is given by P(t) = t 3 – 2t and the velocity ofthe object is given by v(t) = 2t, what is the forceacting on the object in terms of t?

A) 0.5m(4t – 2)2 B) 4m(4t – 2)C) 4m(2t 2 – 2t) D) 4mE) m(4t – 2)

44. If a force moves an object of mass m so that itsvelocity is given by v(t) = 4t – 2, what is the powerexerted by that force?

A) 5(4t – 5) B) 5(2t 2 – 5t)C) 5(2t 2 – 5t)2 D) 2.5(2t2 – 5t)2E) 2.5(4t – 5)2

45. What is the expression of the kinetic energy of anobject of mass 5 kg whose acceleration is given by a(t) = 4t – 5 and that is initially at rest?

A) U(x) = x 3/3 + 2x + kB) U(x) = –x 3/3 – 2x – kC) U(x) = –x 3/3 – 2x + kD) U(x) = –x 3/3 – 2xE) U(x) = x 3/3 + 2x

46. An object with an initial potential energy k experiences a conservative force given by F(x) = x 2 + 2 over the interval 0 × 2. What is theequation for the potential energy U of this object?

A) 16 J B) 20 J C) 32 J D) 44 J E) 80 J

47. An object is pushed by a force given by F(x) = 6x – 4. What is the amount of work done to push theobject 4 m.

A) 2mB) m(2 + x)C) m(4x + x2)D) m(2x2 + 8x + 8)E) m(8x2 + 4x3 + x4/2)

48. The velocity of an object of mass m is given by theequation v = 2x + 4. What is an expression for thekinetic energy of the object?


49. A force acting on an object of mass 3 kg is given bythe equation F(x) = 6x + 2, where F is in Newtonsand x is in meters. If the object starts at rest, what isthe final velocity of the object as it travels from x =0 to x = 4 m?

A) 2.5 kJ B) 5 kJC) 12.5 kJ D) 125 kJE) 250 kJ

50. A 10 kg particle's acceleration is given by theequation a(t) = 4t, where a is in m/s2 and t is inseconds. The particle is initially at rest at the origin.What is the particle's kinetic energy at t = 5 s?

A) 26 J B) 27 J C) 31 J D) 34 J E) 36 J

51. A force acting on an object given by the function F(x) = 3x2 + 4, where F is in Newtons and x is inmeters. What is the change in the object’s kineticenergy as it moves from x = 1 to x = 3 m?

A) –3k B) –k C) Zero D) k E) 3k

52. The potential energy of an object is given by U(x) = 0.5kx2 + 3kx, where U is in joules, x is inmeters and k is a constant. What is the force actingon the object when x = 0?

A) 900 J B) 1000 JC) 1500 J D) 2000 JE) 2705 J

53. A 50 kg car travels along a straight track along the x-axis according to the equation x(t) = t2 + 4t + 5,where x is in meters and t is in seconds. What is thecar’s kinetic energy after 1 s?

A) 155 J B) 175 J C) 200 J D) 225 J E) 400 J

54. A force given by F(x) = 6x + 3x2 acts upon aprojectile that starts from rest at the origin. Howmuch work is done on the 5 kg projectile if it travels5 m?

A) Zero B) 3000 NC) 6000 N D) 12000 NE) 16000 N

55. The position of a vehicle of mass 1000 kg movingon a straight track along the x-axis is given by theequation x(t) = t3 – t2 – 6t, where x is in meters and t is in seconds. What is the instantaneous forceacting on the vehicle at t = 3 s?

A) I only B) II onlyC) I and II only D) II and III onlyE) I, II and III

56. Which of the following statements concerning askier in a valley is true if friction and air resistanceare negligible?I. The skiers speed is maximum at the bottom ofthe valleyII. The skiers speed is at a minimum at the top ofthe valleyIII. The skiers potential energy is zero at the top ofthe valley

A) 10 B) 10C) 20 m/s D) 150 m/sE) 300 m/s

57. What is the velocity of a particle after falling 10meters if its initial velocity is 10 m/s?

A) m/s B) 2 m/sC) 4 m/s D) 8 m/sE) 16 m/s

58. What is the minimum velocity a toy car has to travelin order to survive going through a loop of radius 0.2meters if?

A) 1 meter B) 2.5 metesC) 5 meters D) 25 metersE) 50 meters

59. 5 kg bowling ball in a pendulum assembly is givenan initial velocity of 10 m/s. What is the maximumheight reached by the ball?

A) B)C) D)E)

60. A pendulum of mass m on a massless string oflength l is displaced an angle . What is themaximum velocity of the pendulum?

A) the system becomes more stableB) the system becomes less stableC) the total energy of the system decreasesD) the kinetic energy in the system decreasesE) the system does work on its environment

61. In general, if the center of mass of a system is raisedto a higher gravitational potential and the system isotherwise unchanged,

A) +10J. B) –10J. C) +15J. D) –15J. E) +20J.

62. A block of mass 1 kg at rest slides down africtionless inclined plane as shown in the picture.The plane is sloped at an angle of 30° relative to theground. When the block slides to the ground, itschange in kinetic energy is most nearly

A) 0.0025 N/cm B) 0.005 N/cmC) 0.05 N/cm D) 20 N/cmE) 400 N/cm

63. A 1 N weight depresses a spring 20 cm. What is thespring constant?

A) 0.04 cm B) 0.2 cmC) 20 cm D) 200 cmE) 400 cm

64. If a spring with force constant 0.01 N/cm has apotential energy of 2.0 Joule how far was the springdepressed?

A) 0.0001 Joules B) 0.001 JoulesC) 0.1 Joules D) 0.5 JoulesE) 1 Joule

65. How much work is done compressing a spring 10 cmwith constant 0.01 N/cm?

A) 0.001 N B) 0.01 NC) 0.1 N D) 10 NE) 1,000 N

66. A spring with a force constant of 0.01 N/cm isdepressed 10 cm what is the force exerted on thespring?

A) 25 cm B) 50 cmC) 100 cm D) 500 cmE) 1,000 cm

67. A spring with a force constant of 0.05 N/cm sitsvertically. How far is it depressed when a 5 Nweight is placed on it?

A) 120 N/m B) 240 N/mC) 480 N/m D) 600 N/mE) 960 N/m

68. A 3 kg object is dropped from a height of 4 m onto aspring. The maximum compression of the spring is0.5 m. What is the spring constant?

A) 0.063 J B) 0.125 JC) 1.25 J D) 2.5 JE) 100 J

69. A spring of constant 50 N/m is used to launch a massacross a rough surface. The spring is compressed0.05 m and released. How much work is done byfriction in order to bring the mass to rest?

A) The total energy is greatest when the velocity isgreatest.

B) The total energy is greatest when thedisplacement is greatest.

C) The potential energy is greatest when thedisplacement is least.

D) The kinetic energy is greatest when thepotential energy is least.

E) The total energy varies based on the position ofthe mass.

70. Which of the following is true of the energy of aspring-mass system?

A) 0.40 J B) 0.80 JC) 8.0 J D) 10 JE) 20 J

71. A block of mass 5.0 kg is hung from a verticalspring stretching it 0.40 m. The amount of energystored in the spring is most nearly

A) B)

C) D)

72. Which graph below best represents the relationshipbetween the potential energy stored in a spring (PE)and the force required to keep the spring inequilibrium (F)?

A) B)

C) D)

73. Which graph below best represents the relationshipbetween the potential energy stored in a spring (PE)and the change in the length of the spring from itsequilibrium position (X)?

A) 0.25 J B) 0.50 JC) 1.0 J D) 2.0 JE) 4.0 J

74. A 1.0 kg object is suspended from a spring withconstant k = 16 N/m. The mass is pulled 0.25 mdownward from its equilibrium position and allowedto oscillate. What is the maximum kinetic energy ofthe object?

A) B)C) D)E) 5 MgL

75. Five identical masses of mass M are suspended by aspring stretched a distance of L. If three of themasses are removed, what is the potential energystored in the spring?

A) B)

C) D)

E)

76. A billiard ball of mass m strikes a soft ball of mass 2m with kinetic energy E. If energy is conservedwhat is the velocity of the heavier ball if all itsenergy is transferred?

A) B)

C) D)

E)

77. A block of mass m is sliding on a frictionless surfacewith velocity v. If the block is acted on by a force F for a distance x what is its new velocity?

A) B) C) D) E)

78. A block of mass m is attached to a placed on avertical spring with force constant k. If the spring isdepressed a distance x, what is maximum heightreached by the block?

A) 0.0008 cm B) 0.08 cmC) 2 cm D) 4 cmE) 8 cm

79. A student drops a 0.02 N coin from a 4 meter highwindow onto a spring with a constant of 0.01 N/cm.How far is the spring depressed? Neglect airresistance.

A) B) C) D) E)

80. A bullet of mass m is shot into a spring withconstant k. If the spring depresses a distance x what was the incident velocity of the bullet?

Base your answers to questions 81 through 85 on thediagram below which shows a frictionless track.

A) 1 m/s B) 1.4 m/sC) 2 m/s D) 2.2 m/sE) 3 m/s

81. If an object of mass 5 kg is released from rest at thebeginning of the track, what is its velocity at pointD?

A) It is losing potential energy only.B) It is gaining kinetic energy only.C) It is gaining potential energy and gaining

kinetic energyD) It is losing potential energy and gaining kinetic

energyE) It is gaining heat energy, gaining kinetic

energy, and losing potential energy

82. Which of the following best describes the motion ofan object as it approaches point B, if it was releasedfrom rest at the beginning of the track?

A) It is in static equilibriumB) It is losing kinetic energyC) It is in dynamic equilibriumD) There is a net force acting on the objectE) Its kinetic energy is 25 J

83. If an object is released at the beginning of the track,which of the following is true at point E?

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

84. At which point is an object at rest in stableequilibrium?


85. At which point would an object at rest be in unstableequilibrium?

A) I only. B) I and II only.C) I and III only. D) II and III only.E) I, II, and III.

86. Units of energy include which of the following?

I. JouleII. Ampere-volt per secondIII. Volt-coulomb

A) Its acceleration is zero.B) Its acceleration is at a maximum.C) Its potential energy is at a minimum.D) Its kinetic energy is at a minimum.E) Its potential and kinetic energies are equal

87. A student throws a stone upward at an angle of 30°.Which statement best describes the stone at thehighest point that it reaches?

A) I only. B) I and II only.C) I and III only. D) II and III only.E) I, II, and III.

88. Units of energy include which of the following?

I. Newton-meterII. Ampere-voltIII. Volt-coulomb

89. Base your answer to the following question on thefollowing situation.

An object weighing 10 N swings at the end of a ropethat is 0.72 m long as a simple pendulum. At thebottom of the of the swing, the tension in the stringis 12 N.

A) 0.036 m B) 0.060 mC) 0.072 m D) 0.144 mE) 0.360 m

What is the maximum height above its lowest pointthat the object reaches?

A) v

B) v2

C) v4

D) vE) 4v

90. An object is falling from a height of h in a vacuumand reaches a final velocity of v. When the objecthas fallen a distance of h/2, its velocity is

A) 3.9 m/s B) 5.6 m/sC) 7 m/s D) 7.9 m/sE) 10.4 m/s

91. An object with a mass of 4 kg is released from rest atthe top of a ramp with length 10 m that makes anangle of 30º with the horizontal. The coefficient ofkinetic friction between the block and the ramp is0.4. The speed the block will have when it hastraveled 5 m down the ramp is most nearly


92. A block with a mass of 10 kg slides down africtionless inclined plane of length 25 m and height20 m. It's speed at the bottom is most nearly

A) mL2 2B) –mL2 2C) –mghD) mghE) Cannot be determined from the information

given.

93. A crate with mass m slides down a frictionless rampwith length L and vertical height h. The crate'schange in kinetic energy from the top to the bottomis equal to:

Base your answers to questions 94 and 95 on thediagram below. In the diagram, a box of mass m issliding down a frictionless ramp of length L with anincline of q to the horizontal. The mass takes t seconds to slide down the ramp.

A) mgL t

B) mgLcosq t

C) mgLcosqD) mgLsinqE) Cannot be determined from the information

given.

94. The work done by gravity on the object is equal to

A) B)

C) D)

E)

95. If released from rest at the top, the velocity of theblock at the bottom of the ramp will be

96. Base your answer to the following question on thefollowing information.

Two balls of different masses are set at a height of 3m above the ground on a frictionless table. The ballon the left is of mass 2M and the ball on the right hasa mass of 3M. They both are released simultaneouslyand slide onto the part of the table 2m above theground.

A) +1Mg B) +5MgC) +10Mg D) +15MgE) +20Mg

What is the total energy of the system?

A) 100 J B) 200 J C) 300 J D) 400 J E) 500 J

97. A man standing a certain height above the groundthrows a rock of mass 1 kg straight up with an initialvelocity of 10 m/s. A few moments later, the rockhits the ground with a kinetic energy of 450 J. If theman dropped this rock from rest, how much kineticenergy would it have right before it hits the ground?

A) 50 J B) 100 J C) 450 J D) 800 J E) 950 J

98. A man standing a certain height above the groundthrows a rock straight up with an initial velocity of10 m/s. A few moments later, the rock hits theground with a kinetic energy of 450 J. If the manthrew this rock horizontally with an initial velocityof 10 m/s at the same height, how much kineticenergy would it have just before it hits the ground?

99. Base your answer to the following question on theinformation below.

A 4.0 kg block rests at the edge of a platform that is 20 m above level ground. The block is launchedhorizontally with an initial velocity of 15 m/s.

A) 450 J B) 800 JC) 1050 J D) 1250 JE) 2450 J

The object's kinetic energy when it hits the ground ismost nearly

A) 3.0 s B) 4.0 sC) 6.0 s D) 12.0 sE) 15.0 s

100. A 5 kg object slides 100 m down a frictionlessinclined plane dropping 45 m. It then slides alonga horizontal surface with a coefficient of kineticfriction of 0.75 until it stops. How long does it taketo stop after it leaves the inclined plane?

101. Base your answer to the following question on thepicture below which shows a 3 kg block sliding 50m down a frictionless inclined plane dropping adistance of 30 m.

A) 90 J B) 300 JC) 500 J D) 900 JE) 1500 J

What is the kinetic energy of the block at the end ofthe drop?

A) Final speed is greater than the initial speedB) Final speed is less than the initial speedC) Final speed is zeroD) Final speed is equal to the square root of twice

the height times gE) The final speed is equal to the initial speed

102. A block is slid up an incline with an initial velocityv, such that the frictional force is less than thegravitational force on the incline. Which is trueabout the final speed of the block?

A) 0.25 B) 0.4 C) 0.66 D) 0.75 E) 1

103. A 1 kg block is placed on an incline of 53 degreeswith a spring at the bottom. The incline has aheight of 4 meters and the spring has a forceconstant of 5 N/cm. If the spring is depressed 4cm, what is the coefficient of kinetic friction?

A) 0.5 cm B) 1 cmC) 2 cm D) 3 cmE) 4 cm

104. A spring with a force constant of 1.5 N/cm isdepressed 20 cm. How high is a 1 kg masslaunched if 0.1 Joules are lost to air resistance onthe way up?

A) 0.00125 B) 0.0125C) 125 D) 250E) 1250

105. A spring accelerates a 1 kg mass on ice. The masscomes to a table top and after 1 meter it comes to astop. If the spring constant is 10 N/m and thespring is depressed 5 cm, what is the coefficient ofkinetic friction?

A) 5 Joules B) 15 JoulesC) 75 Joules D) 125 JoulesE) 150 Joules

106. A baseball with mass 2 kg is thrown verticallyupward with a velocity of 10 m/s. If it lands with avelocity of 5 m/s, how much energy has beenexhausted by air resistance?

A) 43.3 J B) 650 JC) 2250 J D) 6350 JE) 9750 J

107. How much energy is required to push a 50 kg mass15 m across a surface with a coefficient of frictionof 0.3 at a constant velocity?

A) mgh B) mgh + FC) mgh – F D) mgh + FhE) mgh – Fh

108. An object is dropped off a cliff of height h and issubjected to an average force of air resistance of F. If the object has a mass of m, the kinetic energy itgains during the fall will be equal to

Base your answers to questions 109 through 111 on the following information.

A roller coaster car starts at Point A and travels alonga frictionless slope traveling to Point E which is at aslightly lower height.


109. The car's speed is the fastest at which point?

A) The net work done in this system is 0 J.B) The net work done in this system is positive.C) The net work done in this system is negative.D) The net work done in this system is 0 for the

roller coaster, but positive for the slope.E) The net work done in this system is positive

for the roller coaster, but 0 for the slope.

110. If it can be assumed that the car has the same speedat points A and E, which of the followingstatements is true?

A) The Gravitational Potential Energy is lower atPoint E than at Point A.

B) The Gravitational Potential Energy is higher atPoint E than at Point A.

C) Friction exists between the wheels of the rollercoaster car and the track.

D) The roller coaster car loses Kinetic Energybetween A and C.

E) The roller coaster car gains Kinetic Energybetween A and C.

111. If it can be assumed that the car has the same speedat points A and E, which of the following can be avalid explanation about the roller coaster car?

A) 0.03 B) 0.04 C) 0.06 D) 0.08 E) 0.12

112. A 4.0 N force is used to accelerate a 2.0 kilogramblock from rest to a velocity of 6.0 m/s. If theforce was applied over a distance of 15 meters, thecoefficient of kinetic friction between the block andthe surface is most nearly

A) 60 J B) 90 J C) 120 J D) 150 J E) 210 J

113. A horizontal force F is used to push a 3.0 kg block,initially at rest, across a floor, with a constantacceleration of 2.0 m/s2. If the frictional forcebetween the block and the floor is 4 Newtons, howmuch work is done by force F on the block tomove it 15 meters?

A) 400 m B) 450 mC) 500 m D) 525 mE) 4,500 m

114. A 3 kg object slides 90 meters down a frictionlessinclined plane dropping 45 meters. It then slidesalong a horizontal surface with a coefficient ofkinetic friction of 1.0 until it stops. How far fromthe base of the inclined plane does it stop?

A) WattB) Joule per secondC) Kilogram meter squared per second cubedD) Kilowatt-hour

115. Of the following, which is NOT a unit of power?





A) 0.5 watts B) 5 wattsC) 50 watts D) 300 wattsE) 1920 watts

118. a 60 kg climber reaches the top of a 40 meter cliffin 8 minutes. What is the average power consumedby the climber?

A) 0.4 s B) 2.5 sC) 5 s D) 1.25 sE) 6.25

119. A small space heater puts out 1,500 watts of heaton average. How long will it take the space heaterto add 3,750 joules of energy to the room?

A) 0 watts B) 1 wattC) 20 watts D) 200 wattsE) 400 watts

120. A skater is sliding on ice at a constant speed of 20m/s for 20 seconds. What is the average powerconsumed by the skater?

A) 100 watts B) 1,000 wattsC) 1,5000 watts D) 22,500 wattsE) 225,000 watts

121. What is the average power consumed by a cranelifting a 150 kg crate 10 meters to a ledge in 15seconds

A) 4 joules B) 40 joulesC) 240 joules D) 2400 joulesE) 144,000 joules

122. How many joules of energy are consumed by a 40watt light bulb in 1 hour of being turned on?

A) WattB) Joule per secondC) Kilogram meter squared per second cubedD) Kilowatt-hourE) Ampere-volt


A) 20 W B) 40 WC) 100 W D) 200 WE) 400 W

124. A crate with mass 40 kg is pulled by a workeralong a surface at a constant velocity for 10 m. Ifthe crate is pulled for 5 s, and the coefficient ofkinetic friction between the surface and the crate is0.5, the power exerted by the worker over this timeis most nearly

125. Base your answer to the following question on Inthe diagram, a box of mass m is sliding down africtionless ramp of length L with an incline of q tothe horizontal. The mass takes t seconds to slidedown the ramp.

A) mgsinq t

B) mgtcosqC) mgtsinqD) mgLsinq

tE) mgLcosq

t

The power exerted by gravity during the slide is

A) B)C) D)E)

126. A block of mass M is moved up a frictionlessincline by a constant force F. The incline has anangle . The block moves up the incline at aconstant velocity of 5 m/s. What is the powerrequired accomplish this situation?

A) 12.5 W B) 25 WC) 60 W D) 125 WE) 210 W

127. What power is needed to lift a person of mass 50 kga vertical distance of 5.0 m in 20 seconds?

A) 2.5 watts B) 40 wattsC) 100 watts D) 4,000 wattsE) 40,000 watts

128. A toy rocket travels upward at 100 m/s. If therocket has to exert a constant force of 40 newtonsto counter gravity and air resistance, how manywatts does the engine put out?

A) 5 watts B) 10 wattsC) 20 watts D) 40 wattsE) 80 watts

129. A runner is moving at 4 m/s. She experiences airresistance force of 20 newtons. What power is sheconsuming

A) 1,000 watts B) 3,500 wattsC) 7,000 watts D) 21,000 wattsE) 49,000 watts

130. A boat motor exerts a force of 7,000 newtons offorce to maintain a speed of 7 m/s how muchpower does the engine have?

A) 0 watts B) 625 wattsC) 6250 watts D) 250,000 wattsE) 10,000,000 watts

131. As a helicopter takes off its engine exerts a force of250,000 N if the aircraft ascends at 40 m/s howmuch power does the engine have?

A) 0 watts B) 8 wattsC) 20 watts D) 40 wattsE) 400 watts

132. A 1 kg block slides down a 30 degree incline at aconstant 4 m/s. How much power is dissipated inthe form of heat by friction?

A) 1 s B) 2 s C) 3 s D) 6 s E) 12 s

133. A 500 N student expends an average power of 250W to climb a 6 m vertical rope at constant velocity.How long does it take for the student to climb therope?

A) 2 W B) 20 WC) 200 W D) 2,000 WE) 20,000 W

134. A 300 N object is lifted 10 m by a crane at aconstant rate in 15 s. The average power expendedto lift the object is


135. A helicopter lifts a large crate weighing 4000 Nexpending a constant power of 8 kW. The crate ismoving upward at a constant velocity of

A) 250 W B) 1,250 WC) 8,000 W D) 16,000 WE) 32,000 W

136. A crane lifts a box upward that weighs 2000 N at aconstant speed of 8 m/s. What is the power input ofthe crane to lift the box?

A) 2,500 WB) 5,000 WC) 7,500 WD) 10,000 WE) 0 W because the object is at a constant

velocity

137. How much power is needed to lift a 100 kg blockvertically upward at a constant speed of 5 m/s?

A) 20 W B) 25 WC) 50 W D) 100 WE) 200 W

138. A person pushes an object with a mass of 50 kgacross a surface with a coefficient of friction of 0.2.If the box moves with a constant velocity of 2.0m/s, the power supplied to the box by the person is

A) 5 W B) 10 WC) 20 W D) 30 WE) 50 W

139. If a mass of 10 kg moves with the velocity v(t) = t2 – 2t + 1, what is the power exerted by theforce pushing the mass at t = 2?

A) 8 N B) 9 N C) 10 N D) 11 N E) 12 N

140. The power delivered to an object at t = 2 s is 170W. The position of the object along the x-axis isgiven by the equation x(t) = 3t2 + 5t + 1, where x isin meters and t is in seconds. Which of thefollowing is closest to the force acting on theobject?

A) 240 W B) 360 WC) 540 W D) 600 WE) 810 W

141. The acceleration of an object is given by theequation a(t) = 2, where a is in m/s2 and t is inseconds. The object is initially at rest at the origin.A constant force of 30 N acts on the object. Whatis the power delivered to the object at t = 9 s?

A) 55 W B) 61 WC) 66 W D) 71 WE) 77 W

142. The velocity of an object is given by the equation v(t) = 2t + 5, where x is in m/s and t is in seconds.A constant force of 6 N acts on the object. What isthe power delivered to the object at t = 3 s?

A) 100 W B) 104 WC) 130 W D) 134 WE) 200 W

143. The position of an object is given by the equation x(t) = t2 + 3t + 4, where x is in meters and t is inseconds. A constant force of 10 N acts on theobject. What is the power delivered to the object att = 5 s?

A) 16 J B) 21 J C) 24 J D) 36 J E) 48 J

144. The power delivered by an object is given by theequation P(t) = 6t – 3, where P is in Watts and t isin seconds. How much work is done by the objectduring the interval 0 < t < 4 s?

A) 3 W B) 6 W C) 7 W D) 8 W E) 10 W

145. The work done by an object is given by theequation W(t) = 3t2 – 5t + 1, where W is in Joulesand t is in seconds. What is the power delivered bythe object at t = 2?

Answer Keyap energy review

1. E2. A3. E4. A5. D6. A7. C8. E9. A10. C11. A12. A13. A14. C15. A16. B17. C18. B19. B20. B21. A22. C23. E24. D25. B26. A27. A28. B29. C30. C31. B32. C33. B34. C35. E36. C

37. A38. E39. C40. B41. D42. D43. C44. B45. D46. C47. C48. D49. C50. C51. D52. A53. A54. C55. E56. C57. B58. B59. C60. A61. B62. E63. C64. D65. D66. C67. C68. E69. A70. D71. D72. B

73. B74. B75. B76. C77. D78. A79. D80. A81. C82. D83. C84. B85. D86. C87. D88. C89. C90. A91. A92. B93. D94. D95. D96. D97. D98. C99. D100. B101. D102. B103. C104. C105. A106. C107. C108. E

109. C110. A111. C112. D113. D114. E115. D116. D117. D118. C119. B120. A121. B122. E123. D124. E125. D126. C127. D128. D129. E130. E131. E132. C133. E134. C135. A136. D137. B138. E139. C140. C141. C142. C143. C144. D

Answer Keyap energy review

145. C

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