# The stone is thrown vertically upward at a speed of 12 m / s. At what height will its kinetic

**The stone is thrown vertically upward at a speed of 12 m / s. At what height will its kinetic and potential energies be equal?**

V0 = 12 m / s.

g = 10 m / s2.

Ek = En.

h -?

The kinetic energy of the stone Ek is determined by the formula: Ek = m * V ^ 2/2, where m is the mass of the stone, V is the speed of the stone.

The potential energy of the body En is determined by the formula: En = m * g * h, where g is the acceleration of the stone, h is the height of the stone above the earth’s surface.

When lifting a stone, the law of conservation of total mechanical energy is valid: Ek0 = Ek + En = 2 * En.

Ek0 = m * V0 ^ 2/2.

m * V0 ^ 2/2 = 2 * m * g * h.

h = V0 ^ 2/4 * g.

h = (12 m / s) ^ 2/4 * 10 m / s2 = 3.6 m.

Answer: at a height of h = 3.6 m, the kinetic energy of the body will be equal to the potential.