Question Video: Changing the Subject of a Formula | Nagwa Question Video: Changing the Subject of a Formula | Nagwa

# Question Video: Changing the Subject of a Formula

Albert Einsteinβs famous formula πΈ = ππΒ², where the constant π is the speed of light, relates the energy, πΈ, contained in matter and its mass, π. Rearrange the formula to make π the subject.

01:29

### Video Transcript

Albert Einsteinβs famous formula πΈ equals ππ squared, where π is the speed of light, relates the energy, πΈ, contained in matter and its mass, π. Rearrange the formula to make π the subject.

In order to rearrange or change the subject of a formula, we need to use our knowledge of inverse operations and the balancing method. In this question, as we want to make π the subject, we need to get this letter on its own on one side of the equation. We begin by dividing both sides of the equation πΈ equals ππ squared by π. The left-hand side becomes πΈ divided by π. And the right-hand side becomes π squared as the πβs cancel.

The inverse or opposite of squaring is square rooting, so we need to square root both sides of this equation. On the left-hand side, we have the square root of πΈ over or divided by π. The square root of π squared is equal to π.

Rearranging the formula πΈ equals ππ squared to make π the subject gives us π is equal to the square root of πΈ over π.

## Join Nagwa Classes

Attend live sessions on Nagwa Classes to boost your learning with guidance and advice from an expert teacher!

• Interactive Sessions
• Chat & Messaging
• Realistic Exam Questions