Question

Question #50ae6

Answer 1

As `T = 2pisqrt(l/g)` the change in period will be an increase of `sqrt2%` or `1.41%`

Explanation:

These sort of questions are very common at this level, so it is best to get good at them (practice) early on. They not only double factor A and ask about B, but also use percentage uncertainty (a bit like this one) in A and get you to combine the uncertainties to predict the effect on B.

The equations they use will almost always be exponential not linear (I.e `y = x^n` where `n != 1`.) Good examples are kinetic energy and velocity, the frequency of a pendulum (the inverse of period, so requires two mental operations/calculations) and orbital motion, whether gravitational or magnetic forces are involved.

If you are finding this tricky, I was less than brilliant at Maths, so used to set the first variable to one unit, then work out on a calculator how the other factor would change. With practice, it has become much easier to do in my head.