Question

Ratio of angular velocity of hour hand of a watch and the angular velocity of rotation of earth is

• A. $1 : 1$
• B. $2 : 1$
• C. $4 : 1$
• D. $1 : 2$

Hint:

Compare periods using $\omega = \dfrac{2\pi}{T}$ to get angular velocity ratios.

Answer 1

The Correct Option is B

Angular velocity $\omega = \dfrac{2\pi}{T}$
$T_{hour\ hand} = 12~\text{hr} = 43200~\text{s}$, $T_{earth} = 24~\text{hr} = 86400~\text{s}$
$\dfrac{\omega_{hour}}{\omega_{earth}} = \dfrac{1/43200}{1/86400} = 2 : 1$