Question

A body A of mass 20 kg is moving with a velocity of 1 ms⁻¹. Another body B of mass 1 kg is moving with a velocity of 20 ms⁻¹. Find the ratio of kinetic energy of A and B.

Answer 1

Kinetic energy (K) \[= \frac{1}{2}\, mv^{2} \]

For body A: \[K_A=\frac{1}{2}\times20\times1^2=10\ \text{J}\]

For body B: \[K_B=\frac{1}{2}\times1\times20^2=200\ \text{J}\]

Therefore, the ratio is K_A : K_B = 10 : 200 = 1 : 20