Question

If the mean speed is 3/4^th of the maximum speed, the coefficient of steadiness is ______

(a) 4/3

(b) 3/2

(c) 3/4

(d) 1

The question was posed to me during an interview for a job.

This question is from Coefficient of Fluctuation of Speed in section Turning Moment Diagrams and Flywheel of Machine Dynamics

Answer 1

The correct choice is (b) 3/2

Best explanation: Let N be the mean speed and N1 and N2 be the maximum and minimum speed respectively,

given N=3N1/4 , N1 = 4N/3

also N = (N1+N2)/2

N = 2N/3 + N2/2 : N2 = 2N/3

maximum fluctuation = N1– N2 = 4N/3 – 2N/3 = 2N/3

mean speed = N

therefore coefficient of steadiness = N/(2N/3)

= 3/2.