Question
A particle slides on surface of a fixed smooth sphere starting from top most point. The angle rotated by the radius through the particle, when it leaves contact with the sphere, is
Solution
B.
See the diagram
Let the velocity be v when the body leaves the surface. From free body diagram,
⇒ v2 = R g cosθ
Again from work-energy principle
change in KE = work done
⇒
v2 = 2gR ( 1 - cosθ)
From Eqs. (i) and (ii)
Rg cosθ = 2gR ( 1 - cosθ )
⇒ 3 gR cosθ = 2gR
⇒