Pendulum 0.9 m long: find its period

A simple pendulum 0.9 m long swings through a small angle (g = 10 m/s²). Find its period.

Step-by-step

1. T = 2π√(L/g) = 2π√(0.9/10) ≈ 1.885
   For small swings a pendulum's period depends only on its length and gravity

Why it works

The period of a small-angle pendulum comes from T = 2π√(L/g): the length sits inside the square root, so quadrupling the length only doubles the period.

Common mistakes

• Writing the formula as 2π√(g/L) with length and g swapped.
• Skipping the division under the root and taking the length itself as the period.

Related

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