Question

If acceleration of $A$ is $2m/s^2$ which is smaller than acceleration of $B$ then the value of frictional force applied by $B$ on $A$ is:

• A. $50N$
• B. $20N$
• C. $10N$
• D. None of these

Answer 1

Answer: (C)

$10N$

Ref. image I

Given that acceleration of block $B$ is $2m/{\sec }^2$

Drawing $FBD$ of $A$ ref. image II

$f_2$ frictional force due to $B$

Now $=\frac{f}{m}=a$

$\Rightarrow \frac{f}{5}=2$

$\Rightarrow f_2=10N$

$10N$ of frictional force is applied by$B$ on $A$