A ball weighing 0.5 kg freely falls from a height of 7 m.At a height of 5 m, its kinetic energy (in J) is …

Given:

H1 = 7 meters – the initial height from which the stone falls;

H2 = 5 meters;

m = 0.5 kilograms is the mass of the ball freely falling from the height H1;

g = 10 m / s ^ 2 – acceleration of gravity.

It is required to determine Ekinetic (Joule) – the kinetic energy of the ball at the height H2.

Since, according to the condition of the problem, air resistance can be neglected, then according to the law of conservation of energy:

E1 potential = E2 potential + Ekinetic;

Ekinetic = E1 potential – E2 potential = m * g * H1 – m * g * h2 = m * g * (H1 – H2) = 0.5 * 10 * (7 – 5) = 5 * 2 = 10 Joules.

Answer: The kinetic energy of a ball at a height of 5 meters is 10 Joules.