Question

Is your mass times the gravitational acceleration of the Earth greater than, less than, or equal to the normal force exerted on you by the chair you are sitting on? Explain.

Answer 1

It depends on whether the whole system is in rest position or not
Case1
If the system iis in rest position the weight=mg will act downwards and the reaction will oppose it upwards according to newtons third law for every action there is an equal and opposite reaction so the upward force and downward force must be equal in order for the system to be in rest
Case 2

If the system is moving downwards the whole weight of the body is greater than the normal reaction opposed by the chair

Case 3

If the system is moving upwards the whole weight of the body will be less thanthe normal reaction