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 (velocity) – Increasing the speed of an object increases its kinetic energy

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

So, the higher an object’s mass is and the faster the object is going, the more energy will be in the object’s 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.

When thinking about fast-moving objects, they must have had a large amount of energy transferred to them. This energy is stored in the object’s kinetic store, which is why fast objects have a large amount of kinetic energy.

Calculating Kinetic Energy

If we want to compare objects with different masses and different speeds, we can use the kinetic energy equation. The equation states that:

  • 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 1000kg 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