Question

The minute hand of a circular clock is 15 cm long. How far does the tip of the minute hand move in 1minute . (Take = 3.14)

Answer 1

Length of minute hand = 15 cm
Since the angle traced by minute hand in 60 min. = $360°$
So the angle traced by minute hand in one minute = $\frac{360}{60}=6°$
And the distance travelled by minute hand in one minute = length of the arc of circle subtending an angle of $6°$ at the centre
So length of an arc = $\left(\theta \times \frac{\mathrm{\pi }}{180}\right)\times r=\left(6\times \frac{3.14}{180}\right)\times 15=1.57\mathrm{cm}$
Therefore the tip of minute hand moves 1.57 cm in 1 minute.