A quarter horse power motor runs at a speed of 600 Ep.m. Assuming 40% efficiency the work done by the motor in one rotation will be:

Options

A. 7.46 J
B. 7400 J
C. 7.46 ergs
D. 74.6 J

Answer

a

Explanation

Here, speed of motor =`(600)/(60)=10 r.p.s`
Power of motor=`1/4hp=(746)/(4)W`
Effective power=`(40)/(100)xx(746)/(4)=74.6 W`
`Work W=("Effecttive powre")/("No. of rotations/sec")`
=`(746)/(10)=7.46 J`.