Gravity Questions

A body falling from rest under gravity passes a certain point $P$. It was at a distance of $400\text{m}$ from $P$, $4\text{s}$ prior to passing through $P$. If $g=10{\text{m/s}}^2$, then the height above the point $P$ from where the body began to fall is:

A particle of mass $100\text{g}$ is thrown vertically upwards with a speed of $5\text{m/s}$. The work done by the force of gravity during the time the particle goes up is: