Temperature and the period of a pendulum For oscillations
of small amplitude (short swings), we may safely model the relationship
between the period \(T\) and the length \(L\) of a simple pendulum with the
equation
$$T=2 \pi \sqrt{\frac{L}{g}}$$
where \(g\) is the constant acceleration of gravity at the pendulum's
location. If we measure \(g\) in centimeters per second squared,
we measure \(L\) in centimeters and \(T\) in seconds. If the pendulum
is made of metal, its length will vary with temperature, either
increasing or decreasing at a rate that is roughly proportional to
L. In symbols, with \(u\) being temperature and \(k\) the proportionality
constant,
$$\frac{d L}{d u}=k L$$
Assuming this to be the case, show that the rate at which the period changes
with respect to temperature is \(k T / 2 .\)