posted by Mota on .
A man drags a sack of flour of mass 50 kg at
constant speed up an inclined plan to a height of 5m. The plane makes an angle of 30„awith the horizontal and a constant frictional force of 200 N acts on the sack down the plane.
1- How much work does the man do
A- against friction.
B- against gravity.
C- against normal force.
2- Total work done by the man.
You should be able to get some or all of these.
They tell you what the friction force is. Multiply that by the distance he moves to get work against friction.
They work against gravity is M g H, where H is the height change.
There can be no work done against a force that is perpendicular to the direction of motion.
That information should help you come up with the answers yourself