A force exactly equal to the weight of your posterior against the chair.
You know positively that the forces there must exactly cancel and add
to zero, otherwise a net, non-zero force would be present, and your butt
would accelerate.
normal force
normal force
A normal force.
y4es
y4es
It exerts normal force to you.
because the floor exerts the same amount of force which means the net force is balanced causing it not to move
Assuming that the seat of the chair is horizontal, and you an penis d the chair are stationary, the key forces here are your weight, which is acting vertically downwards on to the chair, and an equal reaction force, or normal contact force, of the chair acting on you. This force acts vertically upwards. You could also include the forces of the air acting on you and vice versa, but this is probably not what you're after.
Excuse me ... they DO ! That's why, when you sit in a chair and the downward force of your weight against the chair and the upward force of the chair against your bottom exactly cancel, your bottom doesn't go accelerating somewhere.
The pressure caused is created when the normal force of the chair (the chair pushing back against you, as opposed to breaking down) acts against your weight.
AS much as you weigh is the lbs of force that your chair exerts
The chair is pushing up with a force equal to your weight.