Question

A ball of mass 4 kg is dropped from a height of 20 m. Calculate initial momentum and the momentum just before it strikes the ground.

Answer 1

Dear student,
u=0,s=20 m, m=4 kg
Using the equation

$$\begin{gathered} v^2=u^2-2as \\ v=\sqrt{2as} \\ v=19.7m/s \end{gathered}$$

Momentum of the ball is
$$\begin{gathered} p=mv \\ p=4\times 19.7 \\ p=78.8kgm/s \end{gathered}$$

Regards.