Q33
ArithmeticSpeed, Time & Distance
The velocity ratio of the hour hand and minute hand of a clock is
- a.1 : 12
- b.12 : 1
- c.24 : 1
- d.1 : 24
Answer: (A) 1 : 12
The hour hand completes one rotation ($360^{\circ}$) in 12 hours, while the minute hand does so in 1 hour. Since angular speed $\omega=\frac{2\pi}{T}$, we get $\omega_h:\omega_m=\frac{1}{12}:1=1:12$. Option (B) is the inverse (minute hand : hour hand). For comparison, minute hand : second hand $=1:60$ and hour hand : second hand $=1:720$; the hour hand moves $0.5^{\circ}$ per minute and the minute hand $6^{\circ}$ per minute.