What is the kinetic energy of a body weighing 20 kg if its momentum is 800 kg * m / s?

The kinetic energy is found by the formula Ek = m * v ^ 2/2, and the momentum of the body is found by the formula p = mv. To find the kinetic energy, we only lack the speed, but we can find the speed if we derive it from the formula for the momentum v = p / m, now we substitute this into the formula for the kinetic energy Ek = m * (p / m) ^ 2/2
Substitute values
Ek = 20 * (800/20) ^ 2/2 = 1600 (J)
Answer: Ek = 1600 (J)