Question

the minute hand of a clock is 10 cm long .find its displacement and the distance covered from 10 am to 10:30 am

Answer 1

The minute hand of a clock is 10 cm long. Find its displacement and the distance covered from 10 am to 10:30 am.

Solution:

From the time 10 am to 10:30 am minute hand rotates 180 degrees from the 0 minutes position to 30 minutes position.

Hand displacement equals twice the length of hand (hand turned in the opposite position):

$$S = 2 * R = 2 * 10 \text{ cm} = 20 \text{ cm}$$

Distance covered from 10 am to 10:30 ($\alpha = 180{}^{\circ} = \pi$):

$$L = R * \alpha(\text{rad}) = 10 \text{ cm} * \pi = 10 \text{ cm} * 3.14 = 31.4 \text{ cm}$$

Answer: Displacement: 20 cm

Distance: 31.4 cm