Kinetic Energy

Kinetic energy is the energy an object has due to its motion. Everything that is moving has kinetic energy, whether it’s a plane or a particle.

How much kinetic energy an object has depends on two things:

1. Speed or velocity – Increasing the speed or velocity of an object increases its kinetic energy

2. Mass – Increasing the mass of an object increases its kinetic energy

Therefore, an object with greater mass and higher speed will have more energy in its kinetic energy store. This means that if a football and a car were travelling at the same speed, the car would have more kinetic energy because it has a higher mass.

Fast-moving objects have had a significant amount of energy transferred to them, which is stored in their kinetic energy store.

Calculating Kinetic Energy

To compare the kinetic energy of objects with different masses and speeds, we can use the kinetic energy equation. The formula is

  • Kinetic Energy (Ek) is measured in joules (J)
  • Mass (m) is measured in kilograms (kg)
  • Speed (v) is measured in metres per second (m/s)


A motorbike weighs 1000 kg and is travelling at a speed of 10 m/s. Calculate the kinetic energy of the motorbike.

As we are calculating the kinetic energy of the motorbike, we need:

The mass, which is 1000 kg

The speed, which is 10 m/s

So, the equation is:

$\frac { 1 }{ 2 } \times 1000\times { 10 }^{ 2 }=50,000J$