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2D - Momentum Question, Grade 12 Canadian Physics

  • #1

Homework Statement


2 cars collide at an intersection.
one car which has a mass of 1,400kg has a velocity of 45 km/h;
the other car has a mass of 1,300kg and has a velocity of 39 km/h[E]
The cars has an inelastic collision. What are their velocity after the collision


Homework Equations



Conservation of momentum: P total = P total prime


The Attempt at a Solution



I have tried on numerous occasions but have not achieved the correct answer.

The correct answer should be: "30 km/h [ 51 South of East.]

I got the correct magnitude of the velocity which is 30 km/h. Easy enough, but i didn't get the degrees required. Additional vector diagram is appreciated.
 

Answers and Replies

  • #2
993
13
Try to draw the vector diagram for the initial total momentum of the system.
 
  • #3
@grzz I figured out what i did wrong. When i calculated for the theta of the vector triangle. I simply used the velocities. Instead i tried it with m(v) and it worked for me. Thanks.
 
  • #4
993
13
You just confirmed that it is the total momentum that is conserved and not the total velocity!
 

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