# Determine from what height a body weighing 1 kg will fall, if at the moment of its impact on the Earth

**Determine from what height a body weighing 1 kg will fall, if at the moment of its impact on the Earth its kinetic energy was equal to 98 J.**

m = 1 kg.

g = 9.8 m / s2.

Ek = 98 J.

h -?

When the body falls, the law of conservation of total mechanical energy is valid.

The total mechanical energy of the body is conserved.

The total mechanical energy E is the sum of the potential En and the kinetic energy Ek: E = En + Ek.

At the moment of the beginning of the fall, the total mechanical energy of the body consists only of the potential energy En = m * g * h.

At the moment of impact, the total mechanical energy of the body consists only of kinetic energy Ek = m * V2 / 2.

Ek = m * g * h.

h = Ek / m * g.

h = 98 J / 1 kg * 9.8 m / s2 = 10 m.

Answer: the body fell from a height of h = 10 m.