A ball weighing 100 g, flying at a speed of 5 m / s, hit the floor, and then jumped to a height of 0.75 m.

A ball weighing 100 g, flying at a speed of 5 m / s, hit the floor, and then jumped to a height of 0.75 m. How much mechanical energy turned into internal energy upon impact?

m = 100 g = 0.1 kg.

g = 9.8 m / s2.

V = 5 m / s.

h = 0.75 m.

ΔE -?

According to the law of conservation of energy, when the ball is hit, part of the mechanical energy is transferred to the internal one.

Before hitting the ball, mechanical energy consists only of kinetic energy Ek: Ek = m * V ^ 2/2.

At the maximum lifting height h, mechanical energy consists only of potential energy En: En = m * g * h.

ΔE = Ek – En = m * V ^ 2/2 – m * g * h = m * (V ^ 2/2 – g * h).

ΔE = 0.1 kg * ((5 m / s) ^ 2/2 – 9.8 m / s2 * 0.75 m) = 0.515 J.

Answer: ΔE = 0.515 J of mechanical energy passed into the internal energy.