Question

A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure
horizontal rope tied to a wall hold it. The coefficient of friction
between A and the ground is 0.2 while coefficient of friction
between B and the ground is 0.3 . The minimum required force
F to start moving B will be (a) 900 N (b) 100 N(C) 1100 N (d) 1200 N
B​

Answer 1

Answer:

Given that,

m

A

=100Kg

m

B

=200Kg

Let, μ

AB

denotes coefficient of friction between A and B.

μ

AB

=0.2

μ

BG

denotes coefficient of friction between B and ground.

μ

BG

=0.3

Let F be the minimum force required to start moving B.

So,

F=f

AB

+f

BG

=μ

AB

m

a

g+μ

BG

(m

A

+m

B

)g

=0.2×100×10+0.3×300×10

=1100N