Question

1. A pendulum has 15J of potential energy at the top of its swing.

a) What is its kinetic energy at the bottom of its swing?

Answer 1

The law of conservation of energy says

$$E_{k_1}+E_{p1}=E_{k_2}+E_{p2}$$

$$0+15=E_{k_2}+0$$

Hence, the kinetic energy of the pendulum at the bottom of its swing

$$E_{k_2}=\rm 15\: J$$