[Physics] Normal force and reaction

forcesnewtonian-mechanics

It is said that the normal force comes into play any time two bodies are in direct contact with one another, and always acts perpendicular to the body that applies the force. This force is a reactionary force because its value depends on the force the body from which the Normal force is emanating experiences and changes with change in the force applied.

When I apply force on a body at an angle to the normal, even then I am getting a reaction equal to my force. This, too, is emanating from the body that is reacting. So why is the normal special?? When we discuss the free body diagrams of forces applied on bodies, we do not always show this normal – harness attached to a horse, rope on a pulley, wire attached to picture etc.?

Best Answer

This force is a reactionary force because its value depends on the force the body from which the Normal force is emanating experiences and changes with change in the force applied.

No, this is wrong. For example, suppose two cars collide head-on at equal speed. Car A makes a normal force on car B, and B makes a normal force on A. These two forces are Newton's-third-law partners. Newton's-third-law partners are always of the same type, so a normal force is always the "reaction" to a normal force.

So why is the normal special?

It isn't.

When we discuss the free body diagrams of forces applied on bodies, we do not always show this normal

You should.

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