Question:
A person is painting his house walls. He stands on a ladder with a bucket containing paint in one hand and a brush in other. Suddenly the bucket slips from his hand and falls down on the floor. If the bucket with the paint had a mass of $6.0 \mathrm{~kg}$ and was at a height of $2.0 \mathrm{~m}$ at the time it slipped, how much gravitational potential energy is lost together with the paint?
Solution:
Initial P.E. at heiaht $h$.
$P . E_{i}=m g h=6 \times 9.8 \times 2=117.6 \mathrm{~J}$
Final P.E. at the floor,
P. $E_{f}=m g h=0$
P.E. $=117.6-0$
P.E. $=117.6 \mathrm{~J}$