Free Body Diagrams
Finally we add the forces acting on the free body
from outside. In this case they are
your weight W = m g downward
(the gravitational attraction pulling you toward the center of the Earth)
and the normal force N of the ground pushing up on your feet.
Note that both of these forces are applied to you by the Earth.
Because you are not accelerating
(except for a tiny effect due to the rotation of the Earth),
the net force on you must be zero.
This means that the normal force N
must be equal and opposite to your weight W, as shown.
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