Reference: M143
Category: Mechanics
Purpose: Sshows the transformation from potential energy to kinetic energy and back again.
Description: Lower the wooden bar and tighten it so that it stands horizontally. Lift the mass to the height of the bar and release it. The mass swings down and upwards as expected, but the string gets caught on a metal stop. (A movable pin.) The sting bends, but the mass nevertheless rises to the same height as it was dropped from. If this does not occur it is probably because the stop is too low or the bar is too high. In these cases, too much energy is lost is swinging around the pin.
