Question

Einstein once developed the formula, E = mc2, to describe the theory of relativity, where E is the total energy in the system, m is the total mass, and c2 is the speed of light. If the equation was to be rearranged in order to solve for the total mass, which formula below should be used?

A - m = E/c2
B - m = E — c2
C - m = Ec2
D - m = E + c2

Answer 1

The formula which should be used is
`m=(E)/(c^(2))` ⇒ A

Explanation:

To solve an equation of different variables to one of these variables do that

• Write the equation and underline the variable you want to solve for it

• Separate this variable on one side and all other terms on the other sides

Let us do that with the question

∵ E = mc²

→ E is the total energy

→ m is the total mass

→ c² is the speed of light

∵ We need to solve the equation for the total mass m

→ We need to take c² to the other side

∵ c² is multiplied by m

∴ Divide both sides by c² to move it from the right side to the left side

∴
`(E)/(c^(2))=(mc^(2))/(c^(2))`

→ Cancel c² with c² on the right side

∴
`(E)/(c^(2))=m`

→ Switch the two sides

∴
`m=(E)/(c^(2))`

The formula which should be used is
`m=(E)/(c^(2))` ⇒ A