Question

A ball resting on a roof 75 meters high has 1000 Joules of gravitational potential energy. Calculate the mass of the ball. (SHOW ALL WORK)

Answer 1

Answer:

The mass of the ball is 1.360 kilograms.

Explanation:

By Work-Energy Theorem, gravitational potential energy ($U$), in joules, is the product of weight of the ball ($W$), in newtons, and height ($h$), in meters. Please notice that weight is the product of the mass of the ball ($m$) and gravitational acceleration ($g$), in meters per square second. Then, the formula for the mass of the ball is:

$m = \frac{U}{g\cdot h}$ (1)

If we know that $U = 1000\,J$, $g = 9.807\,\frac{m}{s^{2}}$ and $h = 75\,m$, then the mass of the ball is:

$m = \frac{U}{g\cdot h}$

$m = 1.360\,kg$

The mass of the ball is 1.360 kilograms.