A 35 kg child moving at 5 m/s jumps onto a 40 kg sled that is initially at rest on a horizontal ice surface with the coefficient of friction of 0.02.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.