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 ,
W1=Fscosθ=150×3×cos30°=389·7 J
Now again frictional force acting on the block is ,

Fr=μMgcos30°=0·2×20×9·8×32=39·2×32 N
So the work done due to frictional force is ,
W2=μMgcos30°×s=39·2×32×3=101·84 J
Now the net work done to pull the block upwards overcoming the frictional force is ,
Wnet=W1-W2=389·7-101·84=287·85 J

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