Question

A particle of mass 2 kg moves on a circular path with constant speed 10mm/s find change in speed and magnitude of change in velocity when particle completes half revolution

Answer 1

After completing half revolution :
The particle speed remains constant.
The change in speed will be 0 m/sec.
However there is change in velocity vector.
Both(initial velocity& final velocity) have same magnitude but opposite directions(direction of velocity at a point is given by the direction of tangent at that point.so when it completes half rotation the two velocities will be in opposite direction).
So the magnitude of change in velocity will be 20 m/sec.
ie, change in velocity= V - (-V) =10 - (-10)=20