Question #cfd30

1 Answer
Perilous G.
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).

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