Name: ______Core: _____Date: ______

Energy Unit Test – Study Guide

You should be able to explain how kinetic and potential energy contribute to the mechanical energy of an object.

1. What is mechanical energy?

2. What is potential energy?

3. What is the equation for calculating gravitational potential energy (GPE)?

4. What is kinetic energy?

5. What is the equation for calculating kinetic energy?

7. What is the definition of work?

8. How do you calculate the amount of work done in joules (J)?

SHOW YOUR WORK FOR THE FOLLOWING EQUATIONS!!

9. A 20-kilogram (kg) rock falls from a height of 5 meters (m) above the ground. What is the kinetic energy of the rock just before it hits the ground?

10. Jacob lifted a 50-newton (N) bag doing 100 joules (J) of work. How high did he lift the box?

11. What is the mass of an object moving at a speed of 10 meters per second that has 40 joules of kinetic energy?

12. How many joules (J) of work are done if a force of 50 newtons (N) was applied to a pulley to lift an object to a height of 2 meters (m)?

13. What is the kinetic energy of a 1500 kg roller coaster car that is moving at a velocity of 25 meters per second?

14. If the roller coaster in the problem above had twice as much mass, what would be its new kinetic energy?

15. A 50-kg boulder is located on the edge of a cliff 200 meters above the ground. What is the potential energy of the boulder?

16. If we know the mechanical energy of a system is 60 J, and we know the potential energy is 20 J, what is the kinetic energy of the system?

You should be able to explain how energy can be transformed from one form to another (specifically potential energy and kinetic energy) using a model or diagram of a moving object (roller coaster, pendulum, or cars on ramps as examples.)

Refer to the image of the roller coaster below to answer the following questions:

17. At which point on the graph is potential energy the greatest? ____ Why?

18. At which point on the graph is potential energy the least? _____ Why?

19. At which point on the graph is kinetic energy the greatest? _____ Why?

20. At which point on the graph is kinetic energy the least? _____ Why?

21. As the rollercoaster goes from point B to point C, what forces are working against its initial inertia?

Refer to the image of the pendulum below to answer the following questions:

22. At which point on the graph is potential energy the greatest? ____ Why?

23. At which point on the graph is potential energy the least? _____ Why?

24. At which point on the graph is kinetic energy the greatest? _____ Why?

25. At which point on the graph is kinetic energy the least? _____ Why?

You should be able to recognize that energy can be transferred from one system to another when two objects push and pull on each other over a distance (work) and electrical circuits require a complete loop through which an electrical current can pass.

26. Draw an example of a closed electrical circuit, including a light bulb, battery (+ and -), and wires. Label the different types of energy found in the system.

27. Why doesn’t an open electrical circuit cause a light bulb to light up?

Define the following types of energy and give an example of each.

28. Sound energy:

29. Thermal energy:

30: Electrical energy:

40. Chemical energy:

41. Electromagnetic energy:

42. What are renewable resources and what are some examples?

43. What are non-renewable resources ?

44. What are the three types of fossil fuels?

You should be able to explain how simple machines such as inclined planes, pulleys, levers, and wheel and axels are used to create mechanical advantage and increase efficiency.

45. What is the difference between ideal mechanical advantage (IMA) and actual mechanical advantage (AMA)?

46. What is the definition of a simple machine?

47. What is the definition of a complex machine?

Explain how the following simple machines help to make work easier AND give an example of each:

48. Wedge:

49. Wheel and axle:

50. Lever:

51. Inclined Plane:

52. Screw:

53. Pulley:

54. What equation do you use to find the ideal mechanical advantage of a wheel and axle?

55. What equation do you use to find the ideal mechanical advantage of a lever?

56. What equation do you use to find the ideal mechanical advantage of an inclined plane?

57. How do you find the ideal mechanical advantage of a pulley?

Work, KE, PE, and Ideal Mechanical Advantage Calculations (SHOW YOUR WORK, including the equation used!):

58. What is the ideal mechanical advantage of an inclined plane that is 24 meters long and 2 meters high?

59. Which inclined plane would have a greater ideal mechanical advantage, one that is 10 meters long and 2 meters high, or one that is 2 meters long and 10 meters high?

60. A screwdriver is used to pry the lid off a paint can. The resistance arm is 2 centimeters. The effort arm is 30 centimeters. What is the mechanical advantage of the screwdriver?

61. Seth and Joe both have ramps that could help them move a 10 kg box onto the back of a truck, which is 1 meter (m) above the ground. Seth’s ramp is 2 meters long and Joe’s ramp is 3 meters long. Which ramp will require less force to move the box into the bed of the truck?

62. A force of 150newtons (N) was applied to a pulley to lift an object a height of 1meter(m). If 100joules(J) of work was done on the weight, how much work was used to overcome the force of friction in the pulley? (Remember, 1 joule of work is equal to 1 newton of force being applied to an object and moving it 1 meter distance).

63. Which wheel and axle has the greatest mechanical advantage, A or B?

A) Radius of the wheel is 20 m and radius of the axle is 10 m.

B) Radius of the wheel is 40 m and radius of the axle is 10 m.

64. What is the mechanical advantage of a certain simple machine if the output force is 50 N and the input force is 10 N?