In the arrangement shown in figure, coefficient of friction between the two blocks is `mu=1//2`. The force of friction acting between

Options

A. 8N
B. 10N
C. 6N
D. 4N

Answer

A

Explanation

Free body diagrams of the two bodies are as follws

Let acceleration of both the blocks towards left is a. Then
`a=(f-2)/(2)=(20-f)/(4)`
or ` 2f-4=20-f`
or ` 3f=24 or f=8N`
Maximum friction between two blocks can be :
`f_("max")=mu mg=0.5 xx 2 xx 10=10N`
Now, since `f lt f_("max") `
Therefore, friction force between the two blocks is 8N.