Energy

Energy Conservation

1. All energy changes described below are correct except for which one? A. A ball rolling down a hill has gravitational potential energy at the top and kinetic energy at the bottom. B. A hot wheels car rolling along the floor slows to a stop causing its kinetic energy to change into heat through friction. C. A pendulum is let go from rest from some height and accelerates down to its lowest point has kinetic energy at the top and potential energy at the bottom. D. Eating a candy bar causes chemical energy to change into heat energy.

Use the following information for questions 2 - 5. A 1.00kg pendulum bob is on a 1.00m long string and it is released from rest and swings back and forth. It starts from a height of 1.00m above a table, goes down to its lowest point right at the table top and it goes back up to a height of 1.00m in 5.00s?

2. What is the best answer for the type of energy it has at the bottom? A. kinetic B. gravitational potential C. heat D. chemical

3. What is the most likely amount of gravitational potential energy it has half way down? A. 9.80J B. 6.75J C. 2.23J D. 4.90J E. 19.6J

4. If the pendulum bob was changed to be 2.00kg and the string length was the same, what is the best answer for the time to swing back up to its original height? A. 6.00s B. 5.00s C. 4.00s D. 2.00s E. 1.00s

5. If the string length was lengthened and the mass remained the same, which would be the most likely answer for the time to swing back up to its original height? A. 6.00s B. 5.00s C. 4.00s D. 3.00s E. 2.00s