Question

When you weigh yourself, how does the support force of the scale acting on you compare to the gravitational force between you and Earth?

Answer 1

Answer with explanation:

We know that when we weigh ourselves on a scale the scale measures the Reaction force that acts between the scale and the person who wishes to determine his weight.

The free body diagram of the person on a weighing scale is represented in the attached figure.

As we can see for equilibrium

$\sum F_{v}=0\\\\\Rightarrow R-W=0\\\\\therefore R=W$

where,

R is the reaction force between the support and the person

W is the weight of the person which by definition is the force that the earth exerts on the person.

Thus according to the above relation we conclude that that support force of the scale is equal to the gravitational force in magnitude but is opposite in direction.