Question

A 7900 kg truck traveling east at 5 m/s collides with a 1650 kg car traveling 300 south of west at 20 m/s. After the collision at what angle do the two vehicles move. Express you answer in degrees from the positive x-axis. Use a coordinate where north is the +y axis and east is the +x axis.

Answer 1

suspect you mean 30 south of west
momentum east 7900*5 - 1650*20 cos 30
momentum south 1650*20 sin 30

new mass = 7900 + 1650

new mass*speed east = old momentum east
new mass* speed south = old momentum south

Answer 2

M1*V1 + M2*V2 = M1*V + M2*V.
7900*5 + 1650*20[30o+180o] = 7900V+1650V
39500 + 33,000[210o] = 9550V
39,500 -28,579 - 16,500i = 9550V.
10,921 - 16,500i = 9550V.
19,787[-56.5o] = 9550V.
V = 2.07m/s.[-56.5o] S. of E. =
2.07m/s[304o] CCW from +x-axis.