M-EngMom7: Conservation of energy; example: roller on wavy track.

PIRA: Unknown

Equipment: wavy track, short thick stand rod, rubber-tired rod used in M-EngMom6, wooden wedge. It can be found in Set 7, Cabinet 3, Shelf 2.

Procedure: Before lecture adjust the slope of the wavy track with the wedge placed under one end so that when the short stand rod is placed at the higher end and just barely shoved it will just barely coast over the first wave, and hence just over the next, and so on, to be caught in the hand at the end.

In lecture point out that the waves are cut as nearly alike as possible and that the wedge adjustment has been made beforehand. Thus, if one wave is successfully passed by the roller the others should be. You can make the adjustment near enough critical that the students actually grunt to help the roller over each hump.

Next, place the rubber-tired roller at the high point and start it similarly down the track. It comes nowhere near passing the first wave but oscillates a few times in the first hollow.

The disc on a shaft used in M-EngMom6 cannot be used here as it slides part way down the first wavy slope.