Question

Anyone please explain me on how to do the ii) and iii)

Answer 1

http://screencast.com/t/6pI7oRFtzXm8

@Vincent-Lyon.Fr @AravindG

Answer 2

The max force such that no sliding takes place will happen when the static friction between A and B is maxed out right?

Answer 3

ii) Block A must be accelerated without slipping on block B
So friction \(T_{blocks}\) exerted by B on A cannot be greater than \(\mu_{blocks}N_A=\mu_{blocks}M_Ag\)
At the same time, this force is giving A an acceleration a.
So \(a=\dfrac{T_{blocks}}{M_A}=\mu_{blocks}g=0.2\times 10=2\) m/s²

iii) Now go back to {A+B} as your system.
N's second law (horiz) is:

\(P-T_{floor}=(M_A+M_B)\,a\)
Since from question i) \(T_{floor}=P_{min}=3150\) N

then, P = (200+250)x2 +3150 = 4050 N

Answer 4

what is t floor in the second part?

Answer 5

coefficient * the mass of both the blocks right?

Answer 6

\(T_{blocks}\) is the tangent friction force between block B and block A, applied on A.
\(T_{floor}\) is the tangent friction force between block B and the floor, applied on B.