Question

FIND THE SPEED OF THE SECOND HAND OF A CLOCK OF LENGTH 21CM

Answer 1

take length of 2nd hand as radius
total distance in one revolution =2πr
=2*22/7*21=132cm
time in one revolution =60sec
speed=132/60=22/10=2.2cm/sec Answer

Answer 2

Answer:

Speed, s = 2.2 m/s

Explanation:

Speed = distance/time

Distance covered by second hand of a clock, d = 2πr

where, r = radius or length of clock

Time of one revolution, t = 60 seconds

So, $s=\dfrac{2\pi r}{t}$

$s=\dfrac{2\pi \times 21\ m}{60\ s}$

s = 2.199 m/s

or

s = 2.2 m/s

So, the speed of the second hand of a clock of length 21 m is 2.2 m/s. Hence, this is the required solution.