Question

If the minute hand of a clock is 10 cm long, then the distance covered by the tip of minute hand in 1 hour is:

• A. $20\pi \text{cm}$
• B. $40\pi \text{cm}$
• C. $60\pi \text{cm}$
• D. $80\pi \text{cm}$

Answer 1

The correct option is A $20\pi \text{cm}$

Step 1: Given, the length of minute hand of the clock is $10$ cm.

The circumference of the clock is given by $C=2\pi r,$ where $r$ is the radius of the clock.
$\therefore C=2\pi \times 10$
$=20\pi \text{cm}$

Step 2: As the minute hand of the clock completes one revolution in 1 hour. So, the distance travelled by the tip of minute hand in 1 hour is equal to the circumference of the clock.

$\therefore \text{Distance traveled in 1 hour = The circumference of the clock}$
$=20\pi \text{cm}$