Question

For the arrangement shown in 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

We know that , angle of repose is the maximum angle for the body to be stable in the inclined plane and the $\tan \theta =\mu$, where $\mu$ is the coefficient of friction of the incline plane
Here it is given that angle of repose is $\theta ={39}^{\text{o}}$ and incline plane angle is less than angle of repose, hence frictional force is sufficient to hold the block

$f_1>\text{mg sin}\theta \Rightarrow$ friction is static
Hence, $T=0$

Option D is the correct answer