Question

A constant torque of 50 N m is needed to keep a wheel moving at a constant angular speed of 20 rads/s. The amount of work performed by this torque in 5 minutes

• A. 10 KJ
• B. 100 KJ
• C. 300 KJ
• D. 30 KJ

Answer 1

The correct option is C 300 KJ

The work done is given by W= F. S if the motion of the object was in a straight line. If the particle was moving with uniform velocity, then S= V t; V is the linear velocity of the particle.
In case of rotation, the linear parameters are replaced by angular parameters. Hence force F gets replaced by torque and linear velocity by angular velocity.
Thus, work done = $\tau \times \omega t=50\times 20\times 5\times 60=300KJ$
Thus the correct option is (c)