In the following arrangement, the system is initially at rest. The 5-kg block is now released. Assuming the pulley and string to be massless and smooth, the acceleration of block C will be

Options

A. zero
B. `2.5m//s^(2)`
C. `(10)/(7)m//s^(2)`
D. `(5)/(7)m//s^(2)`

Answer

D

Explanation

Block `B` will not move.
`5g-T=5a` (1)
`2T-8g=8(a)/(2)` (2)
`10g-2T=10a` from (1)
`2g=14a`
`a=(g)/(7)`
:. `(a)/(2)=(g)/(14)=(10)/(14)=(5)/(7)m//s^(2)` .