Question

A particle moves in a circular path, 0.4 m in radius, with constant speed. If particle makes 5 revolutions in each second of its motion, the speed of the particle is 

(A) 10.6 m/s 

(B) 11.2 m/s 

(C) 12.6 m/s 

(D) 13.6 m/s

Answer 1

Answer is (C) 12.6 m/s

Using, v = rω 

= r x (2πn) = 0.4 x 2π x 5 

= 0.4 x 2 x 3.14 x 5 

= 12.56 = 12.6 m/s