1. Roller Coaster Debrief Tahoma Jr. High 8 th Grade Science Maple Valley, WA

2. 1. Put the letters A, B, C and D below where in the picture those situations would be A. Point of least potential energy B. Point of greatest potential energy C. Point of least kinetic energy D. Point of greatest kinetic energy A B C D

3. 2. On a roller coaster, there is a motor driven chain that the cars attach to that pull the car up the first hill. What would eventually happen if the cars were allowed to roll down the first hill and no further mechanical energy were added? 3. What would cause this to happen? 4. What types of energy would the motion of the cars be converted to (other than Potential Energy again)? It would eventually stop !! mostly heat – but also some sound (kinetic) and also motion of air (different kinetic) friction (mechanical and air)

4. 5. What happens when hill #2 is the same height as hill #1 and the initial speed is almost zero? 6. Where did the energy needed to get over hill #2 “disappear” to? 7. How can you get the car over hill #2 if it is the same height as hill #1? 8. What must hill #1 provide for the car to complete the circuit? Enough potential (stored) energy to overcome any friction Either more initial speed to overcome any friction or use another motor Mostly converted to heat energy (mechanical and air friction) Won’t make it over 2 nd hill.

5. 9. Does changing the mass make any difference in how fast the coaster goes? (some people wait to get on a full coaster instead of empty one – does it matter?) No – heavy objects fall at the same speed as light ones * in fact, a heavier coaster will put more weight/friction on its axles, slowing it down ! hammer and feather drop the same time on Moon (no air friction)

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