Energy Energy

Answer KeyAnswer Key

1. What two factors determine the kinetic 1. What two factors determine the kinetic

energy in an object, what does it depend onenergy in an object, what does it depend on

Mass and speedMass and speed

2. How does kinetic energy depend 2. How does kinetic energy depend on speed on speed

Kinetic energy increases Kinetic energy increases as speed increasesas speed increases

3. What two factors determine the 3. What two factors determine the potential energy in an object, what potential energy in an object, what does it depend on?does it depend on?

Mass and position Mass and position (height)(height)

4. Look at figure 3 on page 128; determine 4. Look at figure 3 on page 128; determine which vase has more potential energy?which vase has more potential energy?

Vase on top shelf would have Vase on top shelf would have more potential energy because more potential energy because it is higherit is higher..

5. When is chemical energy released?5. When is chemical energy released?

When chemicals are broken When chemicals are broken apart and new chemicals are apart and new chemicals are formedformed

6. Look at figure 8 on page 131; 6. Look at figure 8 on page 131; identify all the forms of energy that identify all the forms of energy that are represented in the photograph.are represented in the photograph.

Kinetic energy of the bike and Kinetic energy of the bike and rider, Potential due to height rider, Potential due to height of hill and chemical in the of hill and chemical in the riders muscles, thermal, riders muscles, thermal, radiant radiant

7. What is the law of conservation of 7. What is the law of conservation of energy? Can energy ever be lost or energy? Can energy ever be lost or gained? If it is not lost or gained what gained? If it is not lost or gained what happens to the energyhappens to the energy??

Energy can never be created Energy can never be created or destroyed, it simply or destroyed, it simply changes form. changes form.

8. Look at figure 9 on page 132; 8. Look at figure 9 on page 132; determine where the ball has the determine where the ball has the most kinetic energy. Where does most kinetic energy. Where does the ball have the most total energy?the ball have the most total energy?

The ball has the most kinetic The ball has the most kinetic energy as it leaves the hand. energy as it leaves the hand. The total energy remains The total energy remains constant. constant.

9. What is an energy transformation?9. What is an energy transformation?

When energy changes from When energy changes from one form to anotherone form to another

10. Explain how energy changes form 10. Explain how energy changes form in a car engine in a car engine

Chemical energy in the Chemical energy in the gasoline changes to kinetic gasoline changes to kinetic or mechanical in the car or mechanical in the car engine, thermal as wellengine, thermal as well

11. Explain the energy transformation 11. Explain the energy transformation that occurs you hear a when a radio that occurs you hear a when a radio playing.playing.

ElectricalElectrical→ Kinetic → Sound → → Kinetic → Sound → Kinetic → electricalKinetic → electrical

12. Explain how thermal energy moves 12. Explain how thermal energy moves

Thermal energy always moves Thermal energy always moves from, higher temperature to from, higher temperature to lower temperature.lower temperature.

13. Describe the energy 13. Describe the energy transformation that occurs when transformation that occurs when you burn a piece of wood. you burn a piece of wood.

ChemicalChemical → thermal → radiant→ thermal → radiant (wood)(wood)14. 14. Identify the form of energy that is Identify the form of energy that is

converted to into thermal energy in converted to into thermal energy in your body.your body.

Chemical, when you digest the Chemical, when you digest the food you eatfood you eat. .

15. Explain how if two vases are side 15. Explain how if two vases are side by side on a shelf, one could have by side on a shelf, one could have more potential energy.more potential energy.

A vase with a greater mass A vase with a greater mass would have more potential would have more potential energy energy

16. Describe the conversion between 16. Describe the conversion between potential and kinetic energy that potential and kinetic energy that occur when you shoot a basketball.occur when you shoot a basketball.

Ball has kinetic energy as it Ball has kinetic energy as it leaves your hands, kinetic is leaves your hands, kinetic is converted to potential as it converted to potential as it rises and then converted to rises and then converted to kinetic as it falls to the kinetic as it falls to the ground.ground.

17. An incandescent light bulb 17. An incandescent light bulb converts 10 percent the electrical converts 10 percent the electrical energy it used into radiant energy.energy it used into radiant energy.

The other 90% is converted to The other 90% is converted to thermal energy.thermal energy.