Question

A. A mass of 5kg is on too of a building of height 10m. Calculate its potential energy.
B. The mass then falls at a speed of 8m/s in 4 secs, find its KE and momentum p. What is the force and impulse the mass transfers to the ground?

Answer 1

$P.E.=mgh=5\times10\times 10=500 joule$

$K.E.=0.5\times m\times v^2$

$K.E=0.5\times 5\times\ 8^2=160joule$

$Force=mg=5\times 10=50tons$

$Impulse= force\times \Delta t=50\times 4=200 Ns$$Momentum=mv=5\times 8=40kgm/s$