A body with a mass of 3 kg changed its speed by 2 meters per second, how much the kinetic energy changed at the same time.

Kinetic energy – the energy of a moving body, depending on the speed squared.
Formula for calculation: Ek = (mv ^ 2) / 2.
Where m – body mass, v – body speed.
For the convenience of calculations, we will assume that the speed of the body was 1 m / s.
Therefore Ek = (3 * 1 ^ 2) / 2 = 1.5 J
When changing the speed, in our case, for simplicity of calculations, increasing it by 2 m / s, we get a speed of 3 m / s.
We get Ek = (3 * 3 ^ 2) / 2 = 27/2 = 13.5 J
13.5 – 1.5 = 12 J
When the speed of the body changes by 2 m / s, the kinetic energy of the body changes by 12 J