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Feb22-12, 02:55 PM
P: 168
Quote Quote by kushan View Post
If the net sum of forces is zero , the object moves with constant velocity.(inertial frame)
But , when this centripetal thing comes in
Suppose we have only a force acting perpendicular to the motion of the body.
then how does this centripetal force comes in , there are 4 fundamental forces and all other forces can be taken from these forces , but centripetal force ?
which fundamental force makes centripetal force ?
and why is that when a satellite revolving around a planet , acted by gravity, force is equated to mv^2/r , but that is analogous to F=ma , so there is only one force acting that is gravity so satellite should fall but it doesnt ...
what is my thinking lacking ?
Whatever way the physicists explain centripetal force, graphical or analytical, I still feel centripetal force is not totally understood.

It appears to me if the rotating object is tied by some physical means to the center of rotation, the force is towards the center, but if the object is not tied to the center then the force is away from the center. Water in a bucket spinning in a vertical circle, satellites are examples of latter case.