A hemispherical tank of radius 100 ft is full of water find

Question

A hemispherical tank of radius 10.0 ft is full of water. Find the work done in pumping the water out of the top of the tank. (See Exercise 20. This problem is similar, except that the weight of each element is 62.4π (radius)² (thickness), where the radius of each element is different. If we let x  be the radius of an element and y be the distance the element must be raised. We have 

Exercise 20

Find the work done in pumping the water out of the top of a cylindrical tank 3.00 ft in radius and 10.0 ft high, given that the tank is initially full and water weighs 62.4 Ib/ft³ (Hint: If horizontal slices dx ft thick are used, each element weighs  lb, and each element must be raised 10 - ft, if is the distance from the base to the element (see Fig. 26.70). In this way, the force, which is the weight of the slice, and the distance through which the force acts are determined .Thus, the products of force and distance are summed by integration.)