Question

A) Logs of a certain wood (specific gravity 0.383) are cylinders of radius 13.3 cm and length 8.42 m. Find the minimum number of logs needed to create a raft to carry a load of mass 8,016 kg when it floats in fresh water (density 1000 kg/m3). Why is using the minimum not practical? NOTE: The answer will most probably include a decimal; give this answer, although in real life you would have to only use a whole number of logs.

B) On January 15, 1919 a cylindrical tank of molasses ruptured, and poured out over the streets of Boston.  Insome places, the stream was 9 m deep; pedestrians and horses were killed, and buildings were knocked down. (This is true!)

Suppose a cylindrical tank (height 26.4 m, diameter 9.81 m) was full of molasses (specific gravity 9.26).  Find the magnitude of the total force exerted by the molasses on the bottom of the tank before it broke.   

Answer 1