Two bodies A and B of mass 5 kg and 10 kg contact with each other rest on a table against a rigid The coefficient of friction between the bodies and the table is 0.05 A force of 200 N is applied horizontal on A What are (a) the reaction of thee wall (b) the the action , reaction forces between A & B ? What happens when the wall is removed ? Does the answer to (b) Change , when the bodies are in motion ? Ignore differnce between `mu_(s)` and `mu_(k)`
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Explanation

Here , mass of body A, `m_(1) = 5 kg`
mass of body B, `m_(2) = 10 kg`
coefficient of friction between the bodies and the table ` mu = 0.15 `
Horizontal force applied on A , `F = 200 N `
(i) Force of limiting friction acting to the left
`f = mu (m_(1) + m_(2) g`
`= 0. 15 (5 + 10 ) xx 9.8 = 22 .05 N`
Net force exerted on the partition (to the right)
`F = F - f = 200 - 22.05 = 177.95 N `
Reaction of partition `= 177 . 95 N` to the left
Force of limiting friction acting on the body A
`f_(1) = mu m_(1) g = 0 .15 xx 5 xx 9.8 = 7 . 35 N`
Net force exerted by body A on body B
`F'' = F - f_(1) = 200 - 7 .35 = 192 . 65 N`
This force is to the right
Reaction of body B on body A = 192 . 65 N to the left
Acceleration produced in the system
`a = (F)/(m_(1) + m_(2)) = (177 . 95)/(5 + 10) = 11 .86 m//s^(2)`
Force producing motion in body A
`F_(1) = m_(1) a = 5 xx 11.86 = 59.3 N`
Net force exerted by body A on B when partition is removed ` = F '' - F_(1) = 192.65 - 59.3 = 133.35 N`
Hence reaction of body B on body A when partition is removed `= 133 . 35 N`
Thus answers to (ii) do change .