Question

Consider a system of a cliff diver and the earth. the gravitational potential energy of the system decreases by 28,000 j as the diver drops to the water from a height of 32.0 m. determine her weight in newtons.

Answer 1

The decrease in gravitational potential energy of the system is given by

$\Delta U = (mg) \Delta h$

where

m is the mass, g is the gravitational acceleration, and $\Delta h$ is the variation of height of the system.

$(mg)$ also corresponds to the weight of the diver, therefore if we rearrange the equation and we use $\Delta U=28000 J$ and $\Delta h=32.0 m$, we can find her weight:

$mg=\frac{\Delta U}{\Delta h}=\frac{28000 J}{32 m}=875 N$