Question

why should force always act at 90 degree in a circular motion?

Answer 1

Answer:

The force as a result does no work, it does not change the speed but only the direction of the objects velocity. Since it is constantly at 90 degrees, as the objects direction deviates the force then again causes it to deviate it's direction, therefore it's trajectory is described by a circle.

Answer 2

Answer:

bro answer it urgently please with solution