When the pivot point of a balance is not at the center of mass of the balance, how is the net torque on the balance calculated

It is calculated as Force × perpendicular distance.

Explanation:

Torque is a rotational force and twisting force that can cause an object to rotate in it's axis. This cause angular rotation.

The torque due to gravity on a body about its centre of mass is zero because the centre of mass is the that point of the body at which the force acts by the gravity that is mg.

But if the pivot point of a balance is not at the centre of mass of the balance, it will be FORCE × PERPENDICULAR DISTANCE because at that point, there is no centre in which the force act on a body by gravity. The distance and force will be use to calculate.

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

be subject to a force andchange its motion