A girl of mass 40 kg is moving with a speed 20 ms−1. What is her kinetic energy?.
2000 J
4000 J
6000 J
8000 J
Given, m = 40 kg
v = 20 ms−1
Kinetic Energy, K. E = 12mv2
= 12×40kg×(20 ms−1)2
= (20×20×20)J
= 8000 J
Hence, her kinetic energy is 8000 J
A body of mass 10 kg is moving with a velocity 20 m s−1. If the mass of the body is doubled and its velocity is halved, find:(i) the initial kinetic energy, and (ii) the final kinetic energy.