Solutions
If the force on a moving body is always uniform and perpendicular to its motion, then speed remains the same, but direction changes.
From the definition of the centripetal force, if a force is perpendicular to the motion, it is a centripetal force and this force makes the body move in a circular motion.
We know the centripetal force acting on a body of mass 'm' revolving with radius 'r' is:
Since F is uniform, so v will also be uniform. So speed (magnitude of velocity) will not change.
In a circular motion, a body moves in a circle, and in a circle the direction of motion changes at every point.
- At point A, the direction of the velocity is in the upward direction.
- At point B, the direction of the velocity is in the leftward direction.
- At point C, the direction of the velocity is in the downward direction.

The body comes in the initial direction after one complete circle. So, if the force on a moving body is always uniform and perpendicular to its motion, then Speed remains the same, but direction changes.