In all of the experimental arrangements the mass of the knif

In all of the experimental arrangements the mass of the knife-edge clamp is ignored. Is this an approximation because its mass is small, or is there some reason it makes no contribution to the torque? State your reasoning clearly.

Solution

The Clamp is positioned near the point of contact around which we calculate the torque. A well placed clamp\'s torque owuld be zero when calculated around the point of contact due to symmetry.

So we can easily Put the torque of clamp to be zero.