Potential energy of an object at a height

Q.

A book of mass $0.5kg$ is lifted vertically upward by using energy of $1J$. The vertical distance through which book is raised:

1. $40cm$

2. $100cm$

3. $50cm$

4. $20cm$

Q.

A stone of mass $5kg$ is lying at the edge of a cliff of $80m$ vertical height from the ground level. Calculate the potential energy of the stone.

[ Take $g=9.8m{s}^{-2}$]

Q.

Discuss an activity that shows that the higher an object is located, the greater its potential energy.