Question

A boy weighing 40 kg makes a high jump of 1.5 m.
(i) What is his kinetic energy at the highest point?
(ii) What is his potential energy at the highest point? (g = 10 m/s²)

Answer 1

(i) The kinetic energy at the highest point is zero because at the highest point, velocity of the high jumper becomes zero.

(ii) Mass of the boy, (m) = 40 kg
Acceleration due to gravity, (g) = 10 m/s²
Height above the ground, (h) = 1.5 m
We can calculate potential energy as,
P.E = (m) (g) (h)
So,
$$\begin{gathered} P.E=\left(40\right)\left(10\right)(1.5)\mathrm{J} \\ =\boxed{600\mathrm{J}} \end{gathered}$$