Question

Two blocks a and b are separated by some distance and tied by a string. the force of friction in both the blocks at t=2sec is

Answer 1

Please find the answer below:

Two blocks a and b are separated by some distance and tied by a string. the force of friction in both the blocks at t=2sec is 6N(→) and 4N(←).

Answer 2

question is incomplete , A complete question is attached in figure.

for block of mass 1 kg ,
friction, $f_1=\mu_1m_1g$
$f_1=0.6\times1\times10=6N$

for block of mass 2kg,
friction, $f_2=\mu_2m_2g$
$f_2=0.5\times2\times10=10N$

now, at t = 2 sec , $F'=2t=2(2)=4N$
you can see that , $f_1>F'$
hence, at limiting condition, $F'=f_1=4N(\rightarrow)$

also you can see that $f_2>F$
limiting condition, $F=f_2=5N(\leftarrow)$

hence, option (A) is correct.