How fast should the car move so that its kinetic energy is halved if the car is moving at a speed of 10 m / s?

Given:

v1 = 10 meters per second – initial vehicle speed;

E2 = E1 / 2 – the kinetic energy of the car has decreased by 2 times.

It is required to determine v2 (meter per second) – the speed of the car with a decrease in kinetic energy.

The kinetic energy of the car in the first case will be equal to:

E1 = m * v1 ^ 2/2, where m is the mass of the vehicle.

The kinetic energy of the car in the second case will be equal to:

E2 = m * v2 ^ 2/2, where m is the mass of the car.

Then:

E2 = E1 / 2;

m * v2 ^ 2/2 = m * v12 / 4;

v2 ^ 2 = v1 ^ 2/4;

v2 = v1 / 2 = 10/2 = 5 meters per second.

Answer: the car must move at a speed of 5 meters per second.