What Speed and Direction Does the Tangled Metal Move Post-Collision?

[aquirk]

Homework Statement

A car with a mass of 1680 kg is traveling directly northeast (45° between north and east) at a speed of 14 m/s (31 mph), and collides with a smaller car with a mass of 1300 kg that is traveling directly south at a speed of 13 m/s (29 mph). The two cars stick together during the collision. With what speed and direction does the tangled mess of metal move right after the collision?
Magnitude __________ m/s
Direction _________ degrees South of east

Homework Equations

m1v1i+m2v2i = v1(m1+m2)

The Attempt at a Solution

i tried plugging my values into this equation to figure out the answer but it doesn't seem to give me the right answer. I am thinking maybe I am doing it wrong becuase there is an angle involved but I am not sure.

 

[AEM]

Homework Statement

A car with a mass of 1680 kg is traveling directly northeast (45° between north and east) at a speed of 14 m/s (31 mph), and collides with a smaller car with a mass of 1300 kg that is traveling directly south at a speed of 13 m/s (29 mph). The two cars stick together during the collision. With what speed and direction does the tangled mess of metal move right after the collision?
Magnitude __________ m/s
Direction _________ degrees South of east

Homework Equations

m1v1i+m2v2i = v1(m1+m2)

The Attempt at a Solution

i tried plugging my values into this equation to figure out the answer but it doesn't seem to give me the right answer. I am thinking maybe I am doing it wrong becuase there is an angle involved but I am not sure.

You're on the right track using conservation of momentum, but you seem to have forgotten that momentum is a vector quantity and therefore you will have an equation for the x-components and an equation fro the y-components. So, yes you need to make use of the angle.