Physics
posted by Anonymous .
A car with a mass of 1700 kg is traveling directly northeast (45 degrees between north and east) at a speed of 14m/s (31mph), and collides with a smaller car with a mass of 1300kg that is traveling directly south at a speed of 18m/s (40mph). The two cars stick together during the collision. With what speed and direction does the tangled mess of metal move right after the collision?

do conservation of momentum in NS, and EW directions. Notice the final velocity then will be a vector you can determine the angle and magnitude from.

M1*V1 + M2*V2 = M1*V + M2*V.
1700*14[45o] + 1300*18[270o]=1700V+1300V
Divide both sides by 100:
17*14[45] + 13*18[270] = 17V + 13V.
238[45] + 234[270] = 30V.
168.3+168.3i 234i = 30V.
168.3  65.7i = 30V.
180.7[21.3o] = 30V.
V = 6.0 m/s[21.3] = 6.0m/s[21.3o] S. of
E.