Awater tank is in the shape of a right circular cone with height 18 ft and radius 12 ft at the top. if it is filled with water to a depth of 15 ft, find the work done in pumping all of the water over the top of the tank. recall that the density of water is δ=62.4 lb/ft3.

The frequency of a tuning fork can be found by the method shown. a long tube open at both ends is submerged in a beaker of water, and the vibrating tuning fork is placed near the top of the tube. the length l of the air column is adjusted by moving the tube vertically. the sound waves generated by the fork are reinforced when the length of the air column corresponds to one of the resonant frequencies of the tube. the smallest value for l for which a peak occurs in sound intensity is 7 cm. l what is the frequency of the tuning fork? the speed of sound in air is 345 m/s. answer in units of hz