Question

A block `A` with mass 100kg is resting on another block `B` of mass 200kg. As shown in figure a horizontal rope tied to a wall hold it. The coefficient of friction between `A` and `B` 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. `700 N`
B. `1050 N`
C. `900 N`
D. `1100 N`

Answer 1

Correct Answer - D

for motion to start
`f ge 0.2 xx 100 g + 0.3 xx 300 g=1100 N`
`F_(min)= 1100 N`.