Energy

1. Energy Answer Key

2. 1. What two factors determine the kinetic energy in an object, what does it depend on • Mass and speed

3. 2. How does kinetic energy depend on speed • Kinetic energy increases as speed increases 3. What two factors determine the potential energy in an object, what does it depend on? • Mass and position (height)

4. 4. Look at figure 3 on page 128; determine which vase has more potential energy? Vase on top shelf would have more potential energy because it is higher. 5. When is chemical energy released? When chemicals are broken apart and new chemicals are formed

5. 6. Look at figure 8 on page 131; identify all the forms of energy that are represented in the photograph. Kinetic energy of the bike and rider, Potential due to height of hill and chemical in the riders muscles, thermal, radiant

6. 7. What is the law of conservation of energy? Can energy ever be lost or gained? If it is not lost or gained what happens to the energy? Energy can never be created or destroyed, it simply changes form.

7. 8. Look at figure 9 on page 132; determine where the ball has the most kinetic energy. Where does the ball have the most total energy? The ball has the most kinetic energy as it leaves the hand. The total energy remains constant.

8. 9. What is an energy transformation? When energy changes from one form to another 10. Explain how energy changes form in a car engine Chemical energy in the gasoline changes to kinetic or mechanical in the car engine, thermal as well

9. 11. Explain the energy transformation that occurs you hear a when a radio playing. Electrical→ Kinetic → Sound → Kinetic → electrical 12. Explain how thermal energy moves Thermal energy always moves from, higher temperature to lower temperature.

10. 13. Describe the energy transformation that occurs when you burn a piece of wood. Chemical→ thermal → radiant (wood) 14. Identify the form of energy that is converted to into thermal energy in your body. Chemical, when you digest the food you eat.

11. 15. Explain how if two vases are side by side on a shelf, one could have more potential energy. A vase with a greater mass would have more potential energy

12. 16. Describe the conversion between potential and kinetic energy that occur when you shoot a basketball. Ball has kinetic energy as it leaves your hands, kinetic is converted to potential as it rises and then converted to kinetic as it falls to the ground.

13. 17. An incandescent light bulb converts 10 percent the electrical energy it used into radiant energy. The other 90% is converted to thermal energy.