Question

For the arrangement shown in the figure the tension in the string is
[Given: ${\tan }^{-1}\left(0.8\right)={39}^{\circ }$]

• A. $6\text{N}$
• B. $6.4\text{N}$
• C. $0.4\text{N}$
• D. Zero

Answer 1

The correct option is D Zero

Here $\tan \theta =0.8$
where $\theta$ is angle of repose
$\theta ={\tan }^{-1}\left(0.8\right)={39}^{\circ }$
The given angle of inclination is equal to the angle of repose. So the $1\text{kg}$ block has no tendency to move.
$\therefore mg\sin \theta =$ force of friction
$\Rightarrow T=0$