A block of 20 kg mass is being pulled up a slope making angle 30° with horizontal by applying force of 150 N acting parallel to slope. Calculate work done by applied, frictional and net force in pulling the load up a distance of 3 m. Coefficient of friction between block and slope is 0.2.

Dear Student ,
The mass of the block is 20 kg and applied force is 150 N .Now , distance travelled by the block is 3 m and coefficient of friction is 0.2.
Now work done by applied force is ,
$W_1=Fs\cos \theta =150\times 3\times \cos 30°=389·7 J$
Now again frictional force acting on the block is ,

$F_r=\mu Mg\cos 30°=0·2\times 20\times 9·8\times \frac{\sqrt{3}}{2}=39·2\times \frac{\sqrt{3}}{2} N$
So the work done due to frictional force is ,
$W_2=\mu Mg\cos 30°\times s=39·2\times \frac{\sqrt{3}}{2}\times 3=101·84 J$
Now the net work done to pull the block upwards overcoming the frictional force is ,
$W_{net}=W_1-W_2=389·7-101·84=287·85 J$
Regards