A body weighing 1 kg, moving at an accelerated rate, increases its speed from

A body weighing 1 kg, moving at an accelerated rate, increases its speed from 2 m / s to 5 m / s. Determine the modulus of change in the kinetic energy of the body.

Given:

m = 1 kilogram – body weight;

v0 = 2 meters per second – initial speed of the body;

v1 = 5 meters per second – the final speed of the body.

It is required to determine dEkin (Joule) – the modulus of change in the kinetic energy of the body.

Let’s find the initial kinetic energy of the body:

E1 = m * v0 ^ 2/2 = 1 * 2 ^ 2/2 = 1 * 4/2 = 4/2 = 2 Joules.

Let’s find the final kinetic energy of the body:

E2 = m * v1 ^ 2/2 = 1 * 5 ^ 2/2 = 1 * 25/2 = 25/2 = 12.5 Joules.

Then:

dEkin = E2 – E1 = 12.5 – 2 = 10.5 Joules.

Answer: the modulus of kinetic energy change is 10.5 Joules.