Question

A 10.kg lead brick falls from a height of 2.0m. Find the momentum as it reaches the ground.

Answer 1

Use the following energy relations

`E_(Grav)=mgh`

`E _(Kinetic) = (1)/(2)m v^(2)`
Then look at momentum put into the kinetic energy formula. Recall

`p=mv`
Now we see that

`E _(Kinetic)= ( p^(2) )/(2m)`
Since the kinetic energy at the end of the fall is the same as the potential (Gravitational) energy at the beginning we set them equal

`mgh= ( p^(2) )/(2m)`

`m√(2gh) = p=62.61 (kgm)/(s)`