A tank is a vertical cylinder with inside diameter of 6ft and a height of 15ft. What is the weight in pounds of the tank, as in the above case, if the tank itself weighs 20 lbs per ft of height?

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.