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

(a) If f be the maximum frictional force acting on the combination of A and B then `f=muR=mu(M_(A)+M_(B))g=0.15(5+10)xx9.8`
=22.05N

Reaction of the wall `=F-f=200-22.05=177.95N`
(b) Force of fricition on body A `f_(A)=muM_(A)g=0.15xx5xx9.8=7.35N`
When the partition is removed the masses move together with an acceleration
`a=("Net force")/("total mass")=(F-f)/(M_(A)+M_(B))=(177.95)/(15)=11.86ms^(-2)`
Yes answer to (b) changes, When the bodies are in motion the force exerted by A on B is given by
`F_(BA)=(f-muM_(A)g)-`(force required to produce an acceleration)
`=(200-7.35)-(5xx11.86)=133.35N`