1. The problem statement, all variables and given/known data A car with a mass of 1400 kg is westbound at 50 km/h. It collides at an intersection with a northbound truck having a mass of 2000 kg and traveling at 40 km/h. What is the initial common velocity of the car and trucks after collision if it's an inelastic collision? 2. Relevant equations p = mv 3. The attempt at a solution So I got this question wrong, but I can't seem to get the right answer no matter how I look at it. I think maybe I lost marks because I didn't use the method the teacher wanted (which is fine with me)?? Let me know guys. m1v1 + m2v2 = (m1 + m2)vf (1400kg)(13.888m/s) + 0 = (1400kg + 2000kg)(vfx) vf = 5.7189... m/s 0 + (2000 kg)(12.5 m/s) = (1400kg + 2000kg)(vfy) vf = 7.35294.. m/s (5.7)2 + (7.3)2 = r2 vf = 9.3 m/s tan-1(7.3 / 5.7 m/s) = 52 N of W = 128 degrees I tried a different approach and found P(car) and P(truck), then P(combined), solved for Vf, but I got the same answer: (1400 kg)(13.888 m/s) = 19443.2 kg m/s West (2000 kg)(12.5 m/s) = 25000 kg m/s North pythagorean theorem... = 31670.77559 kg m/s momentum is conserved so 31670.78 = (2000 + 1400) vf vf = 9.3 m/s!!