Question

Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?

Answer 1

1. A basic pendulum is a little metallic ball (known as a bob) suspended by a light string (thread) from a frictionless, solid support. A simple pendulum is depicted in the illustration.
   
2. A basic pendulum swings from extreme positions to its mean position.
3. The bob is at its highest position at the extreme positions and at its lowest at its mean position.
4. The graphic depicts the energy changes that occur when the bob is in motion. So, when a pendulum swings back and forth, its energy changes in the following order.
   

   Extreme right position-All P.E., No K.E.

   ↓

   Mean position-No P.E. All K.E.

   ↓

   Extreme left position-All P.E., No K.E.

   ↓

   Mean position-No P.E. All K.E.

   ↓

   I Extreme right position-All P.E., No K.E.