**What is kinetic energy?**

Any object that is **moving** has **kinetic energy**.

Kinetic energy (KE) depends on just two factors: **mass** and **speed**. The more massive an object is, and the faster it is moving, the more KE it has.

**How is it calculated?**

The equation for kinetic energy is:

**KE = ½ m v ^{2}**

Where *KE* = kinetic energy, *m* = mass, and *v* = velocity (or 'speed').

As KE is a form of energy, its units are **Joules**. The equation only works if **mass is in kilograms** and **velocity is in metres per second**.

It is important to note that **only velocity is squared** in this calculation. The * ½ *and

**m**do not need to be squared. These are just multiplied together, along with

**v**.^{2}

Let's do a quick example:

In a game of cricket, a child hits the ball, mass 500 g, at a speed of 10 m/s. How much kinetic energy does the ball have?

**KE = ****½ m v ^{2}**

**KE = ****½ x 0.5 kg x (10 m/s) ^{2}**

**KE = ****½ x 0.5 x 100**

**KE = 25 J**

Notice that we had to turn the **mass into kilograms** before putting it in to the equation, and **only the speed** had to be **squared**.

Now see if you can apply this equation in the questions in this activity.