Kinetic Energy

Kinetic energy (abbreviated to KE below - but don't you dare do that in an exam paper!) is the energy of motion or movement energy.

There are three forms of KE

vibrational (the energy due to vibrational motion),

rotational (the energy due to rotational motion), and

translational (the energy due to motion from one location to another).

Generally at KS3 and 4 we consider translational kinetic energy when we look at kinetic energy

The Translational Kinetic Energy (you can just call it kinetic energy!) of an object depends on how fast the object is moving, the faster it goes the higher the kinetic energy it has. If it is stationary it has no kinetic energy!

KE also depends on the mass of the object.

Where

E_k = kinetic energy (in joule)

m = mass (in kg)

v = velocity in m/s

This equation shows us that the kinetic energy of an object is directly proportional to its mass and to the square of its speed.

That means if you double the mass - you double the KE, triple the mass - triple the KE etc. The KE depends on the mass.

It also means that for a doubling speed, the KE will increase by a factor of four; for a triple increase in speed, the KE will increase by a factor of nine; etc. The KE is dependent upon the square of the speed.

KE (like all forms of energy!) is a scalar quantity - it has magnitude (size) but no direction.

Click here for some simple Questions