A block of weight w = 30.0N sits on a frictionless inclined plane, which makes an angle θ = 24.0 degree with respect to the horizontal. A force of magnitude F = 12.2N , applied parallel to the incline, is just sufficient to pull the block up the plane at constant speed. The block moves up an incline with constant speed. Required:
What is the total work Wtotal done on the block by all forces as the block moves a distance L = 4.10m up the incline?

One answer could be erosion

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.