Which of the following is TRUE for a flywheel which is retarding, if T is the torque on the crankshaft at any instant and Tmean is the mean resisting torque?

Which of the following is TRUE for a flywheel which is retarding, if T is the torque on the crankshaft at any instant and Tmean is the mean resisting torque? Correct Answer T –T_mean < 0

Explanation:

• The purpose of attaching the flywheel is to convert a variable torque into a mean torque on the crankshaft, which it does by storing the surplus energy in some strokes and by supplying the stored energy in other strokes.
• As it is given that T is the torque of the shaft before attaching flywheel and T_mean is the torque of the crankshaft after installing flywheel so we can conclude that (T – T_mean) will be the torque of the flywheel. As it is also given that flywheel is retarding so by using basic equation of   

                Torque = (Moment of Inertia) x (Angular acceleration)

• We can say  that if angular acceleration is negative then Torque will also be negative therefore, (T –T_mean) < 0