Question

Find the force required to revolve a body of mass 0.2 kg along circular path of radius 2.5m ,so as to make 100 revolutions in 1 minute.​

Answer 1

Answer is given in the pic.

Answer 2

Given:

Body of mass 0.2 kg moves along circular path of radius 2.5m ,so as to make 100 revolutions in 1 minute.

To find:

Force required for this motion.

Calculation:

First , let's calculate the speed of the body:

$\therefore \: v = \dfrac{100 \times 2\pi r}{60}$

$= > \: v = \dfrac{100 \times 2\pi (2.5)}{60}$

$= > \: v = \dfrac{500\pi}{60}$

$= > \: v = \dfrac{25\pi}{3}$

Now , required centripetal force needed to maintain the circular trajectory:

$\therefore \: f = \dfrac{ m{v}^{2} }{r}$

$= > \: f = 0.2 \times \dfrac{ {( \frac{25\pi}{3}) }^{2} }{2.5}$

$= > \: f =0.2 \times \dfrac{ 625 {\pi}^{2} }{2.5 \times 9}$

$= > \: f = 0.2 \times \dfrac{ 625 {\pi}^{2} \times 4 }{90}$

$= > \: f = 54.76 \: newton$

So, final answer is:

$\boxed{ \bf{ \: f = 54.76\: newton}}$