In the arrangement shown in figure, the ends `P` and `Q` of an unstretchable string move downwards with uniform speed `U`. Pulleys `A` and `B` are fixed. Mass `M` moves upwards with a speed

(a) `2U cos theta` (b) `(U)/(cos theta)` (c) `(2U)/(cos theta)` (d) `U cos theta`

Options

A. `V cos theta`
B. `V // cos theta`
C. `2V cos theta`
D. `2//V cos theta`

Answer

B

Explanation

` U cos theta=V`
`therefore U=(v)/(cos theta)`