Work, Energy and Power Practice Test 1

Transcription

1 Name: ate: 1. How much work is required to lift a 2-kilogram mass to a height of 10 meters?. 5 joules. 20 joules. 100 joules. 200 joules 5. ar and car of equal mass travel up a hill. ar moves up the hill at a constant speed that is twice the constant speed of car. ompared to the power developed by car, the power developed by car is. the same. twice as much. half as much. four times as much 2. Four machines do the amounts of work listed in the table shown. The time they take to do the work is also listed. Which machine develops the most power? Machine Work Time 1,000 joules 5 sec 1,000 joules 10 sec 2,000 joules 5 sec 2,000 joules 10 sec One joule is equivalent to one. newton meter 3. kilogram meter 3. watt 2 newton. kilogram meter 2 second 2 3. garden tractor drags a plow with a force of 500 newtons a distance of 10 meters in 20 seconds. How much work is done?. 25 joules. 1,000 joules. 2,500 joules. 5,000 joules newton block is at rest at the bottom of a frictionless incline as shown in the diagram. How much work must be done against gravity to move the block to the top of the incline?. 10 J 4. machine is able to do 30 joules of work in 6.0 seconds. The power developed by the machine is. 60 J. 80 J. 100 J watt watt. 5.0 watts. 180 watts page 1

2 8. Work is being done when a force. acts vertically on a cart that can only move horizontally. is exerted by one team in a tug of war when there is no movement. is exerted while pulling a wagon up a hill 11. How much work is done on a downhill skier by an average braking force of newtons to stop her in a distance of 10 meters? J J J J. of gravitational attraction acts on a person standing on the surface of the Earth 9. The graph shows the force exerted on a block as a function of the block s displacement in the direction of the force. How much work did the force do in displacing the block 5.0 meters? 12. motor having a maximum power rating of watts is used to operate an elevator with a weight of newtons. What is the maximum weight this motor can lift at an average speed of 3.0 meters per second? N N N N. 0 J. 20 J J. 4.0 J 13. Which action would require no work to be done on an object?. lifting the object from the floor to the ceiling 10. Which term represents a vector quantity?. work. power. force. distance. pushing the object along a horizontal floor against a frictional force. decreasing the speed of the object until it comes to rest. holding the object stationary above the ground page 2

3 newton girl takes 10. seconds to run up two flights of stairs to a landing, a total of 5.0 meters vertically above her starting point. What power does the girl develop during her run?. 25 W. 50. W 16. box is pushed to the right with a varying horizontal force. The graph below represents the relationship between the applied force and the distance the box moves. Force vs.istance. 250 W. 2,500 W What is the total work done in moving the box 6.0 meters?. 9.0 J. 18 J. 27 J. 36 J 15. Which pair of quantities can be expressed using the same units?. work and kinetic energy. power and momentum. impulse and potential energy 17. s shown in the diagram below, a child applies a constant 20.-newton force along the handle of a wagon which makes a 25 angle with the horizontal.. acceleration and weight How much work does the child do in moving the wagon a horizontal distance of 4.0 meters?. 5.0 J. 34 J. 73 J. 80. J page 3

4 18. Student lifts a 50.-newton box from the floor to a height of 0.40 meter in 2.0 seconds. Student lifts a 40.-newton box from the floor to a height of 0.50 meter in 1.0 second. ompared to student, student does. the same work but develops more power 20. Which is an SI unit for work done on an object?.. kg m 2 s 2. kg m s 2. kg m 2 s kg m s. the same work but develops less power. more work but develops less power. less work but develops more power 19. ase your answer(s) to the following question(s) on the information below. 21. The diagram here shows a 1-kilogram aluminum sphere and a 3-kilogram copper sphere of equal radius located 20 meters above the ground. boy pushes his wagon at constant speed along a level sidewalk. The graph below represents the relationship between the horizontal force exerted by the boy and the distance the wagon moves. If the two spheres are allowed to fall freely to the ground, they will experience the same. acceleration. decrease in potential energy. increase in kinetic energy What is the total work done by the boy in pushing the wagon 4.0 meters?. specific gravity. 5.0 J. 7.5 J. 120 J. 180 J page 4

5 22. pendulum swings as shown in the diagram. t which position is the kinetic energy of the pendulum bob least? 25. cart weighing 10 newtons is pushed 10 meters on a level surface by a force of 5 newtons. What is the increase in its potential energy? joule. 50 joules. 100 joules. 0 joules kilogram boy initially at rest skis down the slope as shown. ssuming no frictional loss, what will be his kinetic energy at the bottom of the slope? 26. The diagram shows a cart at four positions as it moves along its track. t which positions is the sum of the potential energy and kinetic energy of the cart the same?. 1,500 joules. 7,500 joules. 15,000 joules. 75,000 joules. and, only. and, only 24. s a falling apple approaches the ground, its potential energy. and, only. all positions, through. decreases. increases. remains the same page 5

6 27. Each of the blocks in the diagrams is lifted vertically for the distance indicated. Which block will gain the most gravitational potential energy? meter spring is stretched from equilibrium to position and then to position as shown in the diagram. ompared to the spring s potential energy at, what is its potential energy at?... the same. twice as great.. half as great. four times as great. 30. Which terms represent scalar quantities?. power and force. work and displacement. time and energy. distance and velocity 28. The kinetic energy of a 10.0-kilogram mass moving at a speed of 5.00 meters per second is J J. 125 J. 250 J page 6

7 31. Which graph best represents the relationship between the kinetic energy (KE) of a moving object as a function of its velocity (v)? 34. The diagram shown represents a frictionless track. 10-kilogram block starts from rest at point and slides along the track..... s the block moves from point to point, the total amount of gravitational potential energy changed to kinetic energy is approximately. 5 J. 20 J. 50 J. 500 J 32. If the speed of an object is doubled, its kinetic energy will be. halved. doubled. quartered. quadrupled 35. What is the approximate potential energy of the block at point?. 20 J. 200 J. 300 J. 500 J 33. s an object falls freely near the Earth s surface, the loss in gravitational potential energy of the object is equal to its. loss of height. loss of mass. gain in velocity. gain in kinetic energy 36. Spring has a spring constant of 140 newtons per meter, and spring has a spring constant of 280 newtons per meter. oth springs are stretched the same distance. ompared to the potential energy stored in spring, the potential energy stored in spring is. the same. twice as great. half as great. four times as great page 7

8 37. In the accompanying diagram, an average force of 20. newtons is used to pull back the string of a bow 0.60 meter. 39. The accompanying diagram shows block, having mass 2m and speed v, and block having mass m and speed 2v. ompared to the kinetic energy of block, the kinetic energy of block is s the arrow leaves the bow, its kinetic energy is. the same. twice as great. one-half as great. four times as great. 3.4 J. 6.0 J. 12 J. 33 J 38. Two vacationers walk out on a horizontal pier as shown in the accompanying diagram. 40. student throws a stone upward at an angle of 45. Which statement best describes the stone at the highest point that it reaches?. Its acceleration is zero.. Its acceleration is at a maximum. s they approach the end of the pier, their gravitational potential energy will. Its potential energy is at a minimum.. Its kinetic energy is at a minimum.. decrease. increase. remain the same page 8

9 cces format version c Educide Software Licensed for use by Problem-ttic Work, Energy and Power Practice Test 1 02/18/