Question

Why we find tangent and normal vector of every curve and surface ? what is purpose of tangent and normal vector?

Answer 1

Consider an object on a rigid curved surface, gravity will act on the object; weighting it downwards
but the surface is in the way. The surface pushes the object in the direction normal to the curve, this is known as the normal force.




Where the curve is flat, the normal force points directly up, and cancels out with the weight force; the object will experience no net force.