Question

A triangular plate of uniform thickness and density is made to rotate about an axis perpendicular to the plane of the paper (a) passing through A, (b) passing through B, by the application of the same force $F$, at C (mid-point of AB) as shown. Now,

• A. angular acceleration in both the cases is the same
• B. angular acceleration for case (a) is larger
• C. angular acceleration for case (b) is larger
• D. there would be no angular acceleration for case (b)

Answer 1

The correct option is C angular acceleration for case (b) is larger

The torque in both the cases would be same.
Using $\tau =I\alpha$ we see that for lesser value of I the angular acceleration would be more. Clearly for case (b) the moment of inertia is lesser implying that the angular acceleration will be more than case (a).