Question

EXAMPLE 1.2: The minute hand of a wall clock is 20 cm automobile.
long. Find (a) the distance covered, and (b) the
displacement of minute hand of the clock from 9:00 am to 9:30 am.​

Answer 1

(a) the distance covered by the minute hand is 62.8 cm.

(b) displacement of the minute hand = 40 cm

Explanation:

Length of minute hand=20 cm

from 9:00 to 9:30 it will form a semicircle.

distance=circumference of semi circle=2πr/2=

$\frac{2 \times 3.14 \times 20}{2}$

=62.8 cm

displacement=diameter of semicircle

diameter=2×radius= 2×20=40 cm