Solving most physics problems involves using equations that relate three or more quantities. For example, F = ma

You will usually be given all the quantities except one. You then use the equation to find the unknown quantity. If the unknown in the equation above is F, then the problem is pretty straightforward. But what if the unknown is a?

The way to solve the problem is to isolate the unknown on one side of the equals sign. This can involve several steps. The essential thing to remember is whatever you do to one side of the equation you must also do to the other side. This way the two sides remain equal.

F = ma If you divide both sides by m and flip the equation right to left, you get a = F/m

Sometimes you may need to add or subtract something on both sides of the equation. For example, solving for a in the equation below, a 2 + b 2 = c 2 We start with a 2 = c 2 - b 2

Finally, we find the square root of both sides to solve for a: a = c 2 - b 2

Often the unknown is in the denominator of a fraction, which first requires multiplying both sides of the equation by the unknown. Suppose we wanted to solve for t in the following equation: v = d/t

First multiply by t to get vt = d Then divide both sides by v: t = d/v