A ball of mass `1kg` is suspended by an inextensible string `1m` long attached to a point O of a smooth horizontal bar resting on fixed smooth supports A and B. The ball is released from rest from the position when the string makes an angle `30^@` with the vertical. The mass of the bar is `4kg`. The displacement of bar when ball reaches the other extreme position (in m) is

Answer

B

Explanation

`Deltabar(x) = (mDelta_(1) + MDeltax_(2))/(m + M) = 0`
`rArr (1(l sin 30^(@) + l sin 30^(@) - x) + 4x)/(1 + 4) = 0`
`rArr` Displacement of bar `= x = 0.2`