A ball connect ed with string is released at an angle `45^(@)` with the vertical as shown in figure.Then the acceleration of the box at this instant will be (mass of the box is equal to mass of ball)

Options

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

Answer

B

Explanation

Let acceleration of box at this is 'a' (towards right).
`FBD` of ball w.r.t. box

Net force in `OP` ditection is zero
`:. T + (ma)/(sqrt2) = (mg)/(sqrt2)`
`FBD` of ball w.r.t. ground

`T cos 45^(@) = ma`
or `T = sqrt2 ma`
Substituting in Eq.(i),we get
`a = (g)/(3)`