Q.

A solid sphere of mass 'm' and radius 'r' is allowed to roll without slipping from the highest point of an inclined plane of length 'L' and makes an angle 30° with the horizontal. The speed of the particle at the bottom of the plane is v1. If the angle of inclination is increased to 45° while keeping L constant. Then the new speed of the sphere at the bottom of the plane is v2. The ratio of v12:v22 is          [2025]

1 1:2  
2 1 : 3  
3 1 : 2  
4 1:3  

Ans.

(1)

Loss in P.E. = gain in K.E.

mgL sinθ=12(75)mv2  v2 sinθ

 v12v22=sin 30°sin 45°=12