Q.

A smooth inclined plane ends in a vertical circular loop, as shown in the figure. A small body is released from height h as shown. If the body exerts a force of three times its weight on the plane at the highest point of circle then the height h=αR. The value of α is               [2026]

1 2  
2 4  
3 3  
4 6  

Ans.

(2)

At highest point

mg+N=mvtop2R

mg+3mg=mvtop2R⇒vtop=4gR

Now C.O.M.E:

mg(h-2R)=12m·4gR⇒h=4R