Question

A body of mass $2kg$ is on an inclined plane inclined at 30${}^0$ to the horizontal. The force applied on it parallel to the plane so that it moves up that slope with the acceleration of $2m{s}^{-2}$ against a frictional force of $5N$ is:

• A. $5N$
• B. $9.8N$
• C. $14.2N$
• D. $18.81N$

Answer 1

Answer: (D)

$18.81N$

$F-(mgsin\theta +\mu mgcos\theta )=ma$
$m=2kg$
$f=\mu mgcos\theta =5N$
$sin\theta =0.5$
$a=2m{s}^{-2}$
$F=(2\times 2)+(2\times 9.81\times 0.5)+5=18.81N$