A 12.58 kg block is slid from a height of 9.16 m down a friction-less incline. It comes to a flat surface and crosses a 5.89 m strip of sandpaper with a coefficient of friction of 0.32. After passing over the sandpaper, the block is traveling on a friction-
less surface again. How fast is the block traveling?

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.