Question

A simple pendulum, composed of a bob of mass $m$ connected to the end of a massless rod, executes simple harmonic motion as it swings through small angles of oscillation.The maximum angular displacement with the vertical is denoted by ${\theta }_{max}$. Frictional effects and variation of acceleration due to gravity are negligible.
Which one of the following would enable you to calculate the length of the pendulum?

• A. The mass of the bob
• B. The period of the oscillations
• C. The tangential acceleration at $\theta =0$
• D. The maximum speed of the bob
• E. The acceleration at $\theta ={\theta }_{max}$

Answer 1

The correct option is B The period of the oscillations

For the small oscillation, the motion of the pendulum can be treat as a simple harmonic motion. So, time period of a SHM is $T=2\pi \sqrt{\frac{l}{g}}$

Thus, time period would enable you to calculate the length of the pendulum.