The pulley shown in the diagram is frictionless. A cat of mass 1kg moves up on the massless string so as to just lift a block of mass 2kg. After some time, the cal stops moving with respect to the string. The magnitude of the change in the cat's accelration is

Options

A. g
B. `g/3`
C. `(2g)/3`
D. `(4g)/3`

Answer

C

Explanation

Initially `T=20N`
So, acceleration `=g`
Finally, `20-T'=2xxa'` …(i)
`T'-10=a'` …(ii)
On adding (i) and (ii)
`a'=(g/3)`
Change in acceleration `=g-g/3`