Question

can someone explain the normal force? where does it come from?

Answer 1

You must understand that in physics we cannot "see" forces. We can only observe a body and conclude about the forces acting on the body depending on its surroundings. Consider a point object lying on a non accelerating( think about this) horizontal surface with no applied externally applied force acting on it. A weight force (determined by the mass of the object) acts on the object itself vertically. (NOTE: Weight force of a body always acts on itself). However as stated before, in my frame of reference, the body is in equilibrium both horizontally and vertically ( You certainly dont see objects lying on a horizontal floor crash through the floor at an acceleration due to gravity). Therefore I conclude that there exists a force acting on the body which counteracts the normal force. This force must have a vertical component equal in magnitude to the weight force and its horizontal component must be zero as the body is in equilibrium in the horizontal orientation with no other external for acting on it. I call this force a normal force( as it is acting "ON THE BODY" perpendicular to the surface on which it is resting). But this force must be "provided" by something. I see that nothing except the surface is in contact with the body. Thus i believe that the surface itself is exerting this normal force on the body.

I can experimentally prove that the force is exerted by the surface.:
It is known that a weighing machine actually reads the force acting ON IT. I place this object on the weighing machine. It reads a certain value say X. Then a force of X is acting on the scale. The only possible cause of this force is the object. Thus the object must be exerting a force of X on the machine. By Newton's third law, the machine "surface" in turn exerts a force on the
object which keeps it in equilibrium on the surface of the weighing machine

Answer 2

dear actually normal force is not a real force ...it is actually the rigidity of a solid from where it comes..and it comes only from ideal solid...............becoz if u will hammer a wood then it is not going to give any normal force and it will break down....so normal force is just the rigidity of a ideal body which stops the object to go inside................

Answer 3

Not so ashish. It IS A REAL FORCE. And by the way, we were talking about point objects here.

Answer 4

okk