A wedge is placed on a smooth horizontal plain and a rat runs on its sloping side. The velocity of the wedge is `v=4ms^(-1)` towards the right. What should be the velocity of the rat with respect to the wedge `(u)`, so that the rat appears to ,move in the vertical direction to an observer stading on the ground?

Options

A. (a)`2ms^(-1)`
B. (b)`4ms^(-1)`
C. (c)`8ms^(-1)`
D. (d)`4sqrt(2)ms^(-1)`

Answer

C

Explanation

`vecv_r=vecv_(rw)+vecv_w`
`v/u=costheta`
`implies implies u=v/(costheta)=4/(cos60^@)=8m//s`