@ soumya
first of all your question are not clear,, which height u are talking about , if a body is moving in a circular path . ??
and about the first question , in that what u have to understand is that when a body is actually moving in a circle then in that case both centripetal and centrifugal forces are acted upon .
and centripetal forces are acting towards the center and centrifugal are acting away from the center .
and also an outward force is acting on the body which supports the motion of body in circular path from outside .
now , if u want to balance it in a circle then obviously u need to equate the outward and centrifugal force , only then the centripetal will put the body in circular path ,
and remember all the force are generated by this centripetal force only ..
if they will not balanced then the object will leave the vertical circle ..
HOPE IT CLEARS YOUR DOUBT , APPROVE MY ANSWER ..
AND ASK YOUR 2ND QUESTION CLEARLY ..
ALL THE BEST ..
