The upward force is the same in both directions.
A box is sitting on a table. The upward force exerted on the box that stops it from falling through the table is known as the force.
An example is a hat sitting on someone's head.
Yes, the reaction force to the partner of an object sitting on a table is the normal force acting upward to hold the object up. It is a result of Newton's third law of motion, where the table exerts an equal and opposite force on the object to support it against gravity.
The reaction force to the downward push of Billy's weight on the chair is the upward force of the chair pushing back on him. The downward force of Billy's weight on Earth is countered by the upward force of gravity acting on him.
When sitting on a chair, the action force is your weight pushing down on the chair, and the reaction force is the chair pushing back up on you with an equal force to support your weight. These forces create an equilibrium that keeps you sitting on the chair.
If the forces on an object are balanced, it won't move. This would apply to a captive balloon, held to the ground by a rope. The upward force of the balloon's buoyancy is balanced by a downward force in the rope, and these must be equal. The same argument for you sitting still in your chair, your weight is balanced by an upward force in the chair.
When sitting still watching TV, the main forces acting on you are the force of gravity pulling you downward and the normal force exerted by the chair supporting you upward. These forces are balanced, resulting in a net force of zero, causing you to remain at rest.
It is a force which acts in the upward direction.
Lift is the upward force that opposes the force of gravity.
The Buoyant Force
No, gravity is a downward force.
If the upward force acting on an object is greater than the downward force (its weight or force of gravity), the object will experience a net upward force causing it to accelerate in the upward direction. This could lead to the object moving upwards, overcoming the force of gravity pulling it downward.