Question

A body of mass $m$ is placed on a rough inclined plane of inclination $\theta$ and coefficient of friction ${\mu }_k$. A force of ($mgsin\theta +{\mu }_{k}mgcos\theta$) is applied in the upward direction, the acceleration of the body is:

• A. $g\sin \theta$
• B. $g(\sin \theta +{\mu }_k\cos \theta )$
• C. $g(\sin \theta -{\mu }_k\cos \theta )$
• D. zero

Answer 1

Answer: (D)

zero

Equating forces along X and Y axes,
$N=mgcos\theta$
Also,
$-mgsin\theta -{\mu }_{k}mgcos\theta -ma+mgsin\theta +{\mu }_{k}mgcos\theta =0$
$\therefore ma=0$