Question #cfd30

1 Answer
Nov 20, 2017

The pendulum must be about 0.25 \text{m} long (or 25 \text{cm}).

Explanation:

The equation for the period of a pendulum is
T \approx 2 \pi \sqrt{\frac{L}{g}}
where T is the period, L is the length and g is acceleration due to gravity (g \approx 9.81 \text{m/s} on earth).

Solve for L:
L \approx (\frac{T}{2 \pi})^2 g

Substitute known values (in SI units):
L \approx (\frac{1}{2 \pi})^2 9.81
L \approx 0.249 \text{m}

As all other values used were in SI units, the answer is in SI units of length (meters).