Two block A and B of masses `6 kg` and `3 kg ` rest on a smooth horizontal surface as shown in figure If coefficient of friction between A and Bb is `0.4` the maximum horizontal force which can make them move without separation is

Answer

36

Explanation

Maximum frictional force on block B `mu m_(B) g = 0.4 xx 3 xx 10 = 12 N`
Hence, maximum acceleration `= (12)/(3) = 4 ms^(-2)`
Hence, maximum force `F = (m_(A) + m_(B)) a = (6 + 3) xx 4 = 36 N`