Asked by jain.pradeep | 26th May, 2019, 06:40: PM

Expert Answer:

In figure II if we consider the direction in which block is moving as positive
the net force would be
F subscript n e t end subscript equals 200 minus 100 equals 100
100 equals space m a
Here the acceleration comes out positive which means acceleration and velocity both are in the same direction.
In figure III
if we consider direction in which the block is moving as positive 
F subscript n e t end subscript equals 100 minus 200 equals negative 100
minus 100 equals m a
here the acceleration is negative which shows acceleration and velocity are in opposite direction.
For figure I it is given in the question that object is moving in circle with constant speed. If the speed is constant than tangential acceleration i.e a subscript t equals 0 and hence there will be no force in tangential direction. Hence the net force is acting towards the centre which is always perpendicular to the velocity for circular motion.

Answered by Utkarsh Lokhande | 27th May, 2019, 11:55: AM