Question

100 J of work is done to change the angular speed of flywheel of mass 4 kg from 20 rpm to 60 rpm then radius of gyration of flywheel :
option
a 1.4
b. 1.18
c. 1​

Answer 1

Answer:

Workdone on a flywheel, W = 100J

initial angular velocity, \omega_0 = 60rpm = 60 × 2π/60 = 2π rad/s

Final angular velocity, \omega = 180rpm = 180 × 2π/60 = 6π rad/s

Now, workdone on a flywheel = change in rotational Kinetic energy

100J = 1/2 I\omega_0^2 - 1/2I\omega^2

200 = I[ (6π)² - (2π)² ]

200 = I[ 36π² - 4π² ]

I = 200/32π² = 0.633 kgm²

Explanation:

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