Question

The Bob of a pendulum has a maximum velocity of 2m/s at it's lowest position, O. calculate the height h of the Bob above O, where it's velocity is zero (Take g=10m/s²)

Answer 1

We can find the height $h$ of the Bob above O from the law of conservation of energy:

$$KE=PE,$$ $$\dfrac{1}{2}mv^2=mgh,$$ $$h=\dfrac{v^2}{2g}=\dfrac{(2\ \dfrac{m}{s})^2}{2\cdot10\ \dfrac{m}{s^2}}=0.2\ m.$$