A block is released from rest at the top of an inclined plane which later curves into a circular track of radius r as shown in figure. The minimum height h from where it should be released so that it is able to complete the circle, is

A block is released from rest at the top of an inclined plane which la

1.	A block is released from rest at the top of an inclined plane which later curves into a circular track of radius r as shown in figure. The minimum height h from where it should be released so that it is able to complete the circle, is
Answer» r `2.5` r `1.5` r `0.5` r Solution :To loop the loop body should not loose contact with the the track anywhere so, `vgesqrt(gr)` Applying LAW of conservation of mechanical energy between points Aand B, i.e., magnitude of change in kinetic energy equals the magnitude of change in potential energy. `rArr""(1)/(2)MV^(2)-0=MG(h-2r)` `(1)/(2)m(sqrt(gr))^(2)=mg(h-2r)rArrh=(5)/(2)r` Hence, h must be atleast EQUAL to `2.5` r.