Question

If linear speed of a second hand of a clock is 1 cm/s , then find the length of second hand of clock.
a. 9.5 cm
b. 13 cm
c. 5.5 cm
d. 15 cm

Answer 1

Given :

The linear speed of the second hand = 1 cm/s

To find :

The length of the second hand .

Solution :

The second's hand covers 2π rad in 60 seconds .

The angular speed of the second hand = 2π / 60 rad/s

radius or length of the second hand = ( linear speed ) / ( angular speed )

=> length = 1 * 60 /  2π

=> length = 9.5 cm ( approx. )

The length of the second hand os nearly 9.5 cm .

Answer 2

Answer:

The answer is 9.42 cm aprox 9.5

Explanation:

We are given -

The linear speed of a second hand of a clock

= 1 cm/s

we all know that a clock hand complete it's whole round in 2π space .

now we know the angular distance covered by a hand of a clock

so , angular speed is

= 2π/60 rad/s

length of a hand of a clock is

= linear speed/angular speed

reason = ( linear distance /time/angular distance/time )

= linear distance / angular distance

= 2πr/2π

= r

so now :

= 1/(2π/60)

= 60/2π

= 9.426 cm

hope you all understand