Apply conservation of momentum to the collision

[~christina~]

Homework Statement

2 automobiles of equal mass approach an intersection. One vehicle is traveling with a velocity of 13.0m/s toward east and other is traveling north with a speed of v_2i. The vehicles collide at the intersection become stuck together and leave parallel skid lines at an angle of 55.0 deg north of east. Speed limit for both cars is 35mi/h and the driver of th northward moving vehicle claims he was within speed limit when it occured. Is he telling truth?

Homework Equations

The Attempt at a Solution

I don't have the masses so how do I do this problem??

I don't have the v2 so I assume I could work with 35mph speed as the initial speed of the other vehicle but other than that I'm not sure what to do... and I don't have final vf after collison

35mph=> 15.646m/s


Help!

 

[Doc Al]

Call the mass of each car "m". You won't need the actual value.

Apply conservation of momentum to the collision. Set up two equations, one for the x-components (East) and one for the y-components (North). Call the final speed vf.

You should be able to solve for v2.

 

[~christina~]

Thank You Doc Al

I got it.