Energy Unit Test Review Answers. 1. What force causes an object to have potential energy? Gravity 2. Kinetic energy is energy of ____________________________

Energy Unit Test Review Answers


1. What force causes an object to have potential energy?

• Gravity2. Kinetic energy is energy of

____________________________. • motion3. There are two things that affect an object’s kinetic

energy. They are m_________ and s_________.• mass. speed.


4. Kinetic energy increases as both m_______ and s__________ _______________________________. (increase or decrease)

• mass. speed. increase

5. Which one has more kinetic energy, a person walking, a person running, or a person riding a bicycle? Why?

• Person riding a bicyclebecause person riding abicycle has the most speed.


6. If a bowling ball and a soccer ball are both moving at the same speed, which one will have more kinetic energy? Why?

• Bowling ball• Because the bowling ball has more mass.


7. If you pick up a grocery bag from the floor and put in on the table, you increase its potential energy. Explain how.

• Grocery bag• Because the grocery bag is farther off of the ground.


8. Label the pictures below as either Kinetic or Potential energy. Then, explain why.

8a. Kinetic energyBecause the arrow is moving.

a. b.


8. Label the pictures below as either Kinetic or Potential energy. Then, explain why.

8b. potential energy Because the bow string is pulled tight and not moving.

a. b.


9. If you wrap a fur coat around a thermometer. Will its temperature rise? Explain why or why not.No.Because heat never comes from warm clothes.


10. If you hold one end of a metal nail against a piece of ice, the end in your hand soon becomes cold. Does cold flow from the ice to your hand? Or does heat flow from your hand to the ice? Explain.

• Heat flows from your hand to the ice. Your hand feels cold because of the large temperature difference between your hand and the nail.


11. Heat transfer is a slow process, meaning it doesn’t happen very quickly. Explain why “firewalkers” can walk safely across a bed of red-hot coals in bare feet.• Heat transfer is slow process. So the

firewalker’s feet do not feel hot as long as he does not stop walking.


12. If you drop a hot rock into a pail of water, the temperature of the rock and the water will change until both are equal. The rock will cool and the water will warm. Is this true if the rock is dropped into the AtlanticOcean?• Yes because heat always flowsfrom hot to cool. But since the Atlantic Ocean is so big, the temperature increase is not noticed.


13. When you step out of a swimming pool on a hot, dry day, you feel quite chilly. Why?

• Some of your body’s thermalenergy has been transferred to the pool water. There is now alarger temperature difference between your skin and the hot air, making you feel chilly.


14. You have 2 beakers of water. Beaker 1 is at 110°C and Beaker 2 is at 45°C. Which picture correctly shows which way the heat will flow?

Beaker 1 → Beaker 2

1110O

C

1110O

C

245°C

245°C


15. Next to each example, tell what kind of heat transfer is taking place: Radiation, Conduction, or Convection. Then, explain why.15a. Conduction• Because the thermometeris touching your tongue, transferring the heat.


15b.Radiation• Infrared waves arethermal, so we canfeel them from afireplace.

Energy Unit Test Review Answers15c.Conduction andConvection.

1. Hot air in the oventouches the glass pan,which transfers the heatto the brownies that theglass pan touch.2. Air in the oven touches the coils, rises, and

then falls onto the top of the brownies.


15d.ConductionHot cocoa touches thespoon and transfers the heat.


15e.Convection

Just like in an oven or in the atmosphere, hot water rises and cold water sinks.

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Energy Unit Test Review Answers. 1. What force causes an object to have potential energy? Gravity 2. Kinetic energy is energy of ____________________________