Question

$12$N of force required to be applied on A to slip on B. Find the maximum horizontal force F to be applied on B so that A and B move together.

Answer 1

Given that,

Mass of block A $=4kg$

Mass of block B $=5kg$

Now, when the blocks move together the acceleration will be same.

If f is the force of friction between A and B

Then,

$F-f=m_{B}a....\left(I\right)$

Now, we know that,

$f=ma$

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

$a=\frac{12}{4}$

$a=3m/s^2$

Now, put the value of a in equation (I)

$F-12=5\times 3$

$F=15+12$

$F=27N$

Hence, the force is $27N$