In the figure the pulley `P` moves to the right with a constant speed `u`. The downward speed of A is `v_(A)` and the speed of B to the right `V_(B)`.

Options

A. `V_(B)=V_(A)`
B. `V_(B)=u+V_(A)`
C. `V_(B)+u=V_(A)`
D. the two blocks have acceleration of the same magnitude.

Answer

B, D

Explanation

By string constrain
`v_(A)+u-V_(B)=0`
or `v_(B)=u+a_(B)`
differentiating both side
`a_(B)=0+a_(A)`