6th Grade Force and Motion Review

1. 1. Use the Law of Conservation of Energy and Mechanical Energy to describe the relationship between kinetic energy and gravitational potential energy.
2. 2. Which bird has more kinetic energy? Which has more potential energy?
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4. 3. Use a distance vs. time graph to describe motion and find speed. Match the following stories to the graphs that represent them.
   1. a. Oliver is walking to school when he remembers his backpack. He turns around to get it. After he starts walking again, he realizes he forgot his lunch. He turns around to get it. Finally, Oliver walks to school.
   2. b. Lisa started walking to her friend's house. When she was almost there, a dog chased her and she ran the rest of the way. Her friend wasn't home, but she talked to her mom for a few minutes then walked home.
   3. c. Heidi is riding a skateboard down a hill. She gains more and more speed until she is going too fast. She crashes into someone's yard and comes to a sudden stop.
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6. 4. No matter where an object is, mass is always the same, but the effect of gravity on that mass (weight) will change with gravity (weigh less on the moon although the mass is unchanged).
7. 5. Ramps decrease the force needed to lift an object by increasing the distance. If both ramps are the same height, which requires less force to push the cart up? What is the trade off?
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9. 6. What is mechanical energy?
10. 7. At what point on the roller coaster is there the greatest: potential energy, kinetic energy, fear.
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12. 8. Jeff runs a 500 m in 90 s.  What is Jeff's average speed?