# Homework Help: Find the angle and the velocity of two cars after collision

1. Nov 11, 2009

1. The problem statement, all variables and given/known data

Two cars are driving on an icy parking lot, searching for a free parking space. The first car has a mass m1= 1000 kg and traveling at a speed of 20 km/h, the second car has a mass of m2= 800 kg and drives perpendicular to the direction of the first car at a speed of 15 km/h. They are not aware of each other and crash, so that their cars slide together at an angle θ along previous direction of the first car.
- With what velocity will the two cars be moving immediately after the collision?
- Find the angle at which the two cars start moving?

http://www.slide.com/s/kqikbbPm1j8EewZiTRju4CCgaHODnfDF?referrer=hlnk [Broken]

2. Relevant equations

p= mv

3. The attempt at a solution

First part: With what velocity will the two cars be moving immediately after the collision?

x-direction: m(1)v(1) + 0= (m(1) + m(2))v(x) → v(x)= m(1)v(1) / (m(1) + m(2))
v(x)= 11.11 km/h
y-direction: 0 + m(2)v(2)= (m(1) + m(2))v(y) → v(y)= m(2)v(2) / (m(1) + m(2))
v(y)= 6.66 km/h

v²= v(x)² + v(y)²
v= 12.95 km/h

Second part: Find the angle at which the two cars start moving?

tan θ= v(y) / v(x)= [m(2)v(2) / (m(1) + m(2))] / [m(1)v(1) / (m(1) + m(2))]= m(2)v(2) / m(2)v(2)= 0.6
θ= 30.96 º

I really need to know if may calculations are correct.
Thank you for helping!

Last edited by a moderator: May 4, 2017
2. Nov 11, 2009

### ideasrule

Yes, they're correct.

3. Nov 11, 2009