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 $k T / 2 .$