I think this is the answer. I hope you can understand.
Answer : Height, h = 20.4 m
Explanation :
It is given that,
Mass of an object, m = 500 g = 0.5 kg
Gravitational potential energy, PE = 100 J
The Gravitational potential energy is the energy which is possessed due to the height and gravity of an object. It is given as :
PE = m g h
where,
h is the height of the cliff.

h = 20.40 m
So, the height of the cliff is 20.4 m.
Answer:
True
Explanation:
Johannes Kepler was a German astronomer, mathematician and astrologer. He proposed a model of the solar system which remains in use, with some modifications. Moreover, he developed the laws of planetary motion which explain how the planets move around the sun. This work was not only significant on its own, but it also provided the foundations for Newton's theory of universal gravitation.