Question

A body of mass 0.4 kg is revolved in a horizontal circle of radius 5 m. If it performs 120 rpm, the centripetal force acting on it is 

(A) 4π² N 

(B) 8π² N 

(C) 16π² N 

(D) 32π² N.

Answer 1

Correct option is (D)  \(32 \ \pi^2 N\)

Given,

m = 0.4kg

r = 5 m

n = 120 rpm

n = 2 rps

Centripetal force F = \(m r \omega^2\)

= \(0.4 \times 5 \times (2 \pi n)^2\)

= \(0.4 \times 5 \times (4 \pi)^2\)

= \(\frac{4}{10} \times 5 \times 16 \pi ^2\)

F = \(32 \ \pi^2 N\)

Answer 2

Correct option is (D) 32π² N.