A small block of mass M moves on a frictionless surface of an inclined plane, as shown in the figure. The angle of the incline suddenly changes from `60^@ "to" 30^@` at point B. The block is initially at rest at A. Assume that collisions between the block and the incline are totally inelastic

The speed of the block at point B immediately after it strikes the second incline is

Options

A. `sqrt(120)ms^(-1)`
B. `sqrt(105)ms^(-1)`
C. `sqrt(90)ms^(-1)`
D. `sqrt(75)ms^(-1)`

Answer

B