SIR, PLS EXPLAIN me about the concept of normal force. SIR, IS THAT NECESSARY THAT NORMAL FORCE ACTS OUTWARDS. WHAT ABOUT WHEN ONE SURFACE IS GLUED TO ANOTHER

The concept of the normal force is a consequence of Newton's 3rd Law: for every action there is an equal and opposite reaction.

For example: The normal force exerted by the saucer on the cup, assuming a level tabletop, is equal in magnitude and opposite in sign to the weight of the cup.

normal force acts against your weight.

when two surface are glued, there will be no molecular interaction between th susrface , I mean they act as one body, both forces between each particles neutralizes ... so net normal force in between surface

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regards

Ramesh