5.4.4. A uniform string with mass density 0.03 lbs/ft, and tension 300 lbs, is xed at. the le end and has a. freely moving right end. The string has length 20 ft. and is initially at rest. with linear displacement. from D to 1. (1) Model this problem mathematically. Note: You must model and explain your choice of boundary conditions. (2) Solve the mathematical model