Question

A defective balance has equal arms and how it works

Answer 1

Answer:

The horizantal beam on such scales is intentionally placed below the rotational axis. As long as the weights are in equilibrium the torque is equal on both sides.

But as soon as the position changes e.g. tipping the left scale down, the torques differ because only the tangential part of the gravitational force vector in relation to the rotational axis contributes to the torque around it. When tipping down the left scale, torque on the left side gets smaller and torque on the right side gets bigger, therefore the right side moves down again until equilibrium is reached (besides some swings to accommodate for the temporary impulse energy).

This effect gets the more pronounced as the distance of the horizontal bar approaches the half length of the bar.

This effect would not be if the horizontal bar went exactly through the axis

Answer 2

Answer:

A false balance has equal arms. An object weight x when placed in one pan and y in the other pan. The true weight of the object is equal to (a) √(xy)