A person weighing 100 kg walked at a speed of 1 m / s. What useful work does he need to do to increase

A person weighing 100 kg walked at a speed of 1 m / s. What useful work does he need to do to increase his speed to 4 m / s

Initial data: m (human weight) = 100 kg; V0 (initial speed of a person) = 1 m / s; V (the speed that a person must develop) = 4 m / s.

Since the useful work will be equal to the change in the kinetic energy of a person, it can be calculated by the formula: Ap = Ek ^ 2 – Ek1 = m * V ^ 2/2 – m * V0 ^ 2/2 = 0.5m * (V ^ 2 – V0 ^ 2).

Let’s perform the calculation: Ap = 0.5 * 100 * (4 ^ 2 – 1 ^ 2) = 0.5 * 100 * 15 = 750 J.

Answer: To increase his speed, a person needs to do useful work of 750 J.