Well, depending on which way you are pushing, it could be one of three forces.
If you are pushing along a table, then it is friction that is preventing the box from moving (or more accurately, static friction).
If you are pushing the box down into the table, then it is the normal force that is at work.
If you are pushing into the air, then it is gravity.
When a heavy desk is not moving, the main forces acting on it are the gravitational force pulling it downward and the normal force pushing back up from the ground to support its weight. These two forces are in equilibrium, which is why the desk remains stationary.
An example of spring force is the force exerted by a compressed or stretched spring as it tries to return to its equilibrium position. When you compress a spring by pushing on it, the spring exerts a force pushing back in the opposite direction.
When you push on a wall, the wall exerts an equal and opposite force back on you, as described by Newton's third law of motion. This is due to the interaction between the force you apply to the wall and the reaction force the wall applies to you. As a result, you may feel the resistance of the wall pushing back against you.
An example of output force is the force exerted by a person lifting a box off the ground. When the person applies a force to lift the box, the box applies an equal and opposite force (output force) back on the person.
The upward force exerted on you while standing on the ground is equal to your weight, as determined by the force of gravity pulling you toward the Earth. This force does not lift you up because it is balanced by the force exerted by the ground pushing back on you (normal force), keeping you in equilibrium and preventing you from accelerating upward.
static friction
gravity
When a heavy desk is not moving, the main forces acting on it are the gravitational force pulling it downward and the normal force pushing back up from the ground to support its weight. These two forces are in equilibrium, which is why the desk remains stationary.
An example of spring force is the force exerted by a compressed or stretched spring as it tries to return to its equilibrium position. When you compress a spring by pushing on it, the spring exerts a force pushing back in the opposite direction.
he is holding a stack of books on his back but he is not moving
If there was no friction, your foot would simply slide back as you tried to take steps, and you would go nowhere. In order for something to move, it has to have a force moving it. That force has to have leverage, or friction. For the force pushing a person forward, there is an equal force pushing backward on the ground or floor. You can observe this by placing round pencils under a board, stand on it, and try to step off in the perpendicular direction : the board will roll backward as you step forward.
When you push on a wall, the wall exerts an equal and opposite force back on you, as described by Newton's third law of motion. This is due to the interaction between the force you apply to the wall and the reaction force the wall applies to you. As a result, you may feel the resistance of the wall pushing back against you.
1. Inertia 2. Friction 3. A force when you move your pen or hand
An example of output force is the force exerted by a person lifting a box off the ground. When the person applies a force to lift the box, the box applies an equal and opposite force (output force) back on the person.
When an airplane is motionless on the tarmac, discounting any winds, there are two primary forces acting on it. First is the force of gravity pushing downwards, and secondly, there is the reactionary force pushing back upwards.
The upward force exerted on you while standing on the ground is equal to your weight, as determined by the force of gravity pulling you toward the Earth. This force does not lift you up because it is balanced by the force exerted by the ground pushing back on you (normal force), keeping you in equilibrium and preventing you from accelerating upward.
The action force of walking is the force exerted by the foot pushing against the ground to propel the body forward. This force is equal in magnitude and opposite in direction to the reaction force exerted by the ground pushing back against the foot, allowing us to move forward with each step.