d'. "\"r' Initial position NOT E: This problem requires using two fundamental principles. We're looking down on two positions {\"initial\" and "f: nal\"} of a springmass system that moves on a lowfriction table, with the left end of the spring tied to'the statio new' black ball, which is free to turn. In the initial position the spring was relaxed,with a length of d; = 28 cm. and the sine of the angle 9,- was 0.50. In the nal position the length of the spring is df = 42.0 cm, Fl}. is 0.31 kg'rn/s, and the sine of the angle 9; is 0.35. The mass of the red ball is 0.7 kg. Part 1 What was the magnitude I 3 J of the initial momentum