$\backslash$#$5)$ Suppose that $80$ ft $-1$ b of work are required to stretch a perticular spring from its natural length of $2$ ft to length of $3$ ft $.$

a$)$ How much work is required to stretch the spring from a length of $3$ ft to a length of $4$ ft $?$

b$)$ How far beyond its nahural will a force $24016$ keep the spring stretch ed$?$ How much work is required to stretch the spring this for from its nalural length?

simplify answers and include appropriate units?