# Question #35835

Apr 17, 2016

$E = D V {c}^{2}$

#### Explanation:

Both equations have one thing in common: $m$. You're going to want to rearrange one of them to make $m$ the subject, and then substitute this into the other equation.

For example,

$D = \frac{m}{V}$

multiply both sides by $V$ and you get

$D V = m$.

Since these two are equivalent, you can insert this into $E = m {c}^{2}$, like so

$E = m {c}^{2}$
$E = D V {c}^{2}$

since ${c}^{2}$ is just a constant, you can now find energy given density and volume.