Energy of Objects in Motion Classwork and Homework www.njctl.org - - PDF document

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Energy of Objects in Motion Classwork and Homework www.njctl.org - - PDF document

Slide 1 / 109 Slide 2 / 109 Energy of Objects in Motion Classwork and Homework www.njctl.org Slide 3 / 109 Classwork #1: Energy Slide 4 / 109 1 Define Energy. Slide 5 / 109 2 What are the two things necessary for work to be done on an


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www.njctl.org

Energy of Objects in Motion Classwork and Homework

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Classwork #1: Energy

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1 Define Energy.

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2 What are the two things necessary for work to be done on an object?

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3 How can you determine the amount of work is being done on an object?

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4 What would happen to an object’s velocity if positive work is done on an object?

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5 Based on the diagram below, is positive or negative work being done on the object? Explain.

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6 Based on the graph below, is positive or negative work being done on the object? Explain.

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7 A ball is dropped from the roof of the building. The ball initially had 100 J of Energy. Just as it landed it had 90 J or Energy. How much work was done on the ball as it fell? What did the work?

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8 What are the two major forms of Energy?

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9 What is the definition of Mechanical Energy?

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10 What is the definition of Non-Mechanical Energy?

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Homework: Energy

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11 What would happen to an object’s velocity if no work was being done on the object?

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12 Based on the diagram below, is the object’s speed increasing or decreasing due to Air Resistance. Explain in terms of work being done on the

  • bject.

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13 Based on the graph below, which of the following is being done: positive work, negative work, no

  • work. Explain.

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14 At what time on the graph below does the object start to experience negative work being done on it? Explain.

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15 An adult is driving a car which has 50 J of Energy. At the end of the drive the car still had 50 J of

  • energy. How much work was done on the car

during the drive?

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16 What are the two forms of Mechanical Energy?

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17 Name two forms of Non-Mechanical Energy.

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Classwork #2: Kinetic Energy

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18 What two factors does Kinetic Energy depend upon?

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19 If an object is accelerating, how does its Kinetic Energy change?

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20 If a mouse and an elephant have the same kinetic energy, can you determine which one is running faster? Explain.

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21 If an object’s speed is doubled, how does its Kinetic Energy change?

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22 If the mass of an object is doubled, how does its Kinetic Energy change?

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23 How much kinetic energy does an 80 kg man have while running at 3 m/s?

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24 A 6 kg object has a speed of 20 m/s. What is its kinetic energy?

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25 A 1000 kg car’s velocity increases from 5 m/s to 10 m/s. What is the change it the car’s kinetic Energy?

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Homework: Kinetic Energy

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26 What is the SI unit for Kinetic Energy?

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27 When is the only time that an object has no Kinetic Energy?

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28 If an object is decelerating, how does its Kinetic Energy change?

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29 If an object’s speed is cut in half, how does its Kinetic Energy change?

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30 If the mass of an object is cut in half, how does its Kinetic Energy change?

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31 How much kinetic energy does a 4 kg cat have while running at 9 m/s?

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32 A 2 kg watermelon is dropped from a roof and is traveling with a speed of 5 m/s just before it hits the ground. How much Kinetic Energy does the watermelon have at this moment?

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33 A 700 kg horse is running with a velocity of 5 m/s. How much larger is the horse’s Kinetic Energy compared to a 100 kg man running at the same speed?

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Classwork #3: Gravitational Potential Energy

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34 What three factors does Gravitational Potential Energy depend upon?

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35 If an object is thrown up in the air, how does its Gravitational Potential Energy change?

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36 If an object is falling, how does its Gravitational Potential Energy change?

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37 How does your Gravitational Potential Energy change if you are placed on the moon where gravity is lower than on Earth?

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38 If the mass of an object is cut in half, how does its Gravitational Potential Energy change?

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39 A 1 kg ball is thrown up in the air and reaches a height of 5 m. What is its Gravitational Potential Energy at that moment?

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40 A 200 kg boulder is sitting on top of a 10 m high

  • hill. What is the boulder’s Gravitational Potential

Energy?

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41 What is the gravitational potential energy of a 450 kg car at the top of a 25 m parking garage?

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42 A 2.0 kg toy falls from 2 m to 1 m. What is the change in GPE?

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43 A small, 3 kg weight is moved from a height of 5 m to a height of 8 m. What is the change in potential energy?

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Homework: Gravitational Potential Energy

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44 What is the SI unit for Gravitational Potential Energy?

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45 When is the only time that an object has no Gravitational Potential Energy?

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46 How does your Gravitational Potential Energy change if you are placed on Jupiter where gravity is larger than on Earth?

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47 If the mass of an object is doubled, how does its Gravitational Potential Energy change?

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48 A 75 kg skydiver is spotted at a height of 1000 m above the Earth’s surface. How much Gravitational Potential Energy does the skydiver possess?

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49 A placekicker in football is attempting a field goal and kicks a 0.75 kg football which hits the crossbar that is 3.1 m tall. How much Gravitational Potential Energy does the ball have when it hits the crossbar?

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50 The “Green Monster” is the name for the left field wall at Fenway Park and is 11.33 m tall. How much Gravitational Potential Energy does a 0.2 kg baseball have when it just clears the wall?

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51 An 80 kg person falls 60 m off of a waterfall. What is her change in GPE?

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52 A 0.25 kg book falls off a 2 m shelf on to a 0.5 m

  • chair. What was the change in GPE?

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Classwork #4: Elastic Potential Energy

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53 What two factors does Elastic Potential Energy depend upon?

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54 Define the term spring constant?

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55 The same spring is stretched by 1 meter and then compressed by 1 meter. In which case will the spring have more Elastic Potential Energy stored in it? Explain.

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56 Two identical springs are stretched. Spring A is stretched 1 meter while spring B is stretched 2

  • meters. Which spring will have more Elastic

Potential Energy stored in it? Explain.

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57 If a spring is stretched twice as far (as in #56), how many times larger is the Elastic Potential Energy that is stored in it?

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58 A spring with a spring constant of 500 N/m is stretched 1 meter in length. How much Elastic Potential Energy does the spring have stored in it?

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59 A spring with a spring constant of 250 N/m is stretched 0.5 meters. How much Elastic Potential Energy does the spring have stored in it?

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60 A spring with a spring constant of 100 N/m is compressed by 0.25 meters. How much Elastic Potential Energy does it have stored in it?

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Homework: Elastic Potential Energy

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61 Define the term “Relaxed Length”.

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62 Two springs are stretched to the same distance. If spring A has a spring constant of 200 N/m and spring B has a spring constant of 400 N/m, which spring has more Elastic Potential Energy stored in it? Explain.

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63 A spring with a spring constant of 100 N/m is not

  • stretched. How much Elastic Potential Energy

does the spring have stored in it?

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64 A spring with a spring constant of 200 N/m is stretched 1 meter in length. How much Elastic Potential Energy does the spring have stored in it?

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65 A spring with a spring constant of 500 N/m is compressed 0.5 meters. How much Elastic Potential Energy does the spring have stored in it?

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66 A rubber band with a spring constant of 150 N/m is stretched by 0.25 meters. How much Elastic Potential Energy does it have stored in it?

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Classwork #5: Conservation of Energy

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Questions 67 - 70 refer to the diagram below

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67 At which position does the block have maximum Gravitational Potential Energy? Explain.

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68 At which position does the block have maximum Elastic Potential Energy? Explain.

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69 At which position does the block have maximum Kinetic Energy? Explain.

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70 At which position does the block have maximum Total Energy? Explain.

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Questions 71 – 74 refer to the diagram below

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71 At which position does the man have maximum Gravitational Potential Energy? Explain.

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72 At which position does the man have maximum Elastic Potential Energy? Explain.

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73 At which position does the man have maximum Kinetic Energy? Explain.

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74 At which position does the man have maximum Total Energy? Explain.

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Homework: Conservation of Energy

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Questions 75-78 refer to the diagram below

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75 At which position does the ball have maximum Gravitational Potential Energy? Explain.

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76 At which position does the ball have maximum Elastic Potential Energy? Explain.

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77 At which position does the ball have maximum Kinetic Energy? Explain.

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78 At which position does the ball have maximum Total Energy? Explain.

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Questions 79-82 refer to the diagram below

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79 At which position does the car have maximum Gravitational Potential Energy? Explain.

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80 At which position does the car have maximum Elastic Potential Energy? Explain.

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81 At which position does the car have maximum Kinetic Energy? Explain.

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82 At which position does the car have maximum Total Energy? Explain.

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Classwork #6: Types of Energy Resources

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83 Define Renewable Resource.

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84 Define Non-Renewable Resource.

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85 List two examples of a Renewable Energy Resource.

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86 List two examples of a Non-Renewable Energy Resource.

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Homework: Types of Energy Resources

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87 How does a turbine convert Kinetic Energy of its source into Electrical Energy?

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88 How does a hydroelectric power plant transfer both Potential and Kinetic Energy into Electric Energy?

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89 What type of Energy resource does not use a turbine to convert Mechanical Energy into Electrical Energy?

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90 Why are Fossil Fuels considered to be non- renewable energy resources?

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91 Why are Fossil Fuels not considered clean energy resources?

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