A sphere of radius `R` is in contact with a wedge. The point of contact is `( R)/(5)` from the ground as shown in figure.Wedge is moving with velocity `20 m s^(-1)` towards left then the velocity of the sphere at this instant will be

Options

A. `20 ms^(-1)`
B. `15 ms^(-1)`
C. `16 ms^(-1)`
D. `12 ms^(-1)`

Answer

B

Explanation

`cos theta = (4R//5)/(R ) = 0.8`

`:. theta = 37^(@)`
`(v_(1))/(v_(2)) = tan theta = tan 37^(@) = (3)/(4)`

`:. V_(1) = (3)/(4) v_(2) = (3)/(4) xx 20 = 15 m//s`