(4) (7 pts} Set up, but do NOT evaluate, the integral needed to determine the mass It! of a tree trunk with a radius of 2 m and radial density approximated by p(:r) = w 2 + coshm) , in kgf-mz, with a: in meters (m). Do NOT Evaluate. (5) (10 pts) A spring that obeys Hooke's law has a spring constant :1: = 4 N/m and a natural length I = 6 meters (m). This spring starts in an initial position held stretched 2 meters longer than its natural length. Compute the additional work (and units} required to stretch the spring from the initial position given to being fully stretched 4 meters longer than its natural length. LI\