Momentum in 2-D

  • #1

Homework Statement


A 850 kg car is traveling west at 25.0 m/s when it collides with a 1050 kg car that was initially traveling north at 10.5 m/s. The cars lock together, and eventually skid to a stop.
What is the velocity of the cars immediately after the collision?

Homework Equations


pi=pix i + piy j + piz k


The Attempt at a Solution


I got an answer but I'm not sure if it is correct. I just need someone to verify if what I did is correct.
Here's what I did:
I found pi using the equation above and then took the magnitude of that to find pf as shown below:

(-(850 kg)(25.0 m/s) i)2 + ((1050 kg)(10.5 m/s) j)2=pf2

I then took the pf value and set that equal to the total mass times the velocity:

2.39 x 104 kg*m/s=(850 kg + 1050 kg)v

I then solved for v to get the following:

v=12.6 m/s
 

Answers and Replies

  • #2
rl.bhat
Homework Helper
4,433
8
Your answer is correct.
 

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