Physics - NLM Question with Solution | TestHub

The maximum frictional force on$1^{\mathrm{s}\mathrm{t}}$block due to$2^{\mathrm{n}\mathrm{d}}$block is acting towards left as the accelerating force is acting towards the right. Its value is${\mathrm{f}}_{1\mathrm{m}\mathrm{a}\mathrm{x}}=\mathrm{\mu m}\mathrm{g}$

Now for$2^{\mathrm{n}\mathrm{d}}$body,${\mathrm{f}}_1$acting towards right is responsible to move block towards the right, but${\mathrm{f}}_2$will act towards the left to hold the body in rest. Its value is

${\mathrm{f}}_{2\mathrm{m}\mathrm{a}\mathrm{x}}=\frac{\mathrm{\mu }}{3}\left(3\mathrm{ }\mathrm{m}\mathrm{g}\right)=\mathrm{\mu m}\mathrm{g}$



$\mathrm{T}+{\mathrm{f}}_2={\mathrm{f}}_1$

$\mathrm{T}+\mathrm{\mu }\mathrm{mg}=\mathrm{\mu }\mathrm{m}\mathrm{g}$

$\mathrm{T}=0$

$\Rightarrow$Tension will be zero in all circumstances. Hence A, B and D all the three are correct.

Note- In the second block, we can very clearly see that T=0. It is independent of the force applied as$2^{\mathrm{n}\mathrm{d}}$block is free from any external force.