5} A force of 2D lb is needed to stretch a spring 10 em from its 1 131-113. natural position HDW much work is needed to stretch it 2 111-11) from x = 5 to x = 15 em? {The natural length corresponds to I = .) 4 III-1b 6 111-113 H Find the volume of the solid of revolution obtained by rotating the region bounded by 1 1 y: 553,3}: ?r, andmz. about the ysxis. mlgow'gmlswls