An explosion blows a rock into 3 parts. Two peices go off at right angles to eachother, a 1.0 kg piece at 12 m/s and a 2.0 kg piece at 8 m/s. The third piece flies off at 40 m/s. a) Draw a vector diagram to show the direction in which the third piece goes. I don't know how I can determine which direction it goes b) What is its mass? I don't know how I can get this if I am unable to determine the total momentum.