A concrete slab of uniform thickness weighs 20,000 lb and is supported by two steel rods, as shown. The initial length of rod AB is 2 ft. The initial length of rod CD is 3 ft. Rod AB has an area of 1...

A concrete slab of uniform thickness weighs 20,000 lb and is supported by two steel rods, as shown. The initial length of rod AB is 2 ft. The initial length of rod CD is 3 ft. Rod AB has an area of 1 in. and rod CD has an area of 2 in². Calculate

a. the elongation of each rod.

b. the required ratio of the areas of AB and CD so that the elongation of each bar is the same.