# Homework Help: Velocity before collision

1. Jan 21, 2012

### jmoser

A car with a mass of 1007 kg is moving 36 m/s, strikes a 2499 kg car at rest. if the two cars stick together, with what speed do they move?

I tried using the equation mass of object 1st car*(initial velocity of car 1 + initial velocticy
of car 2) the divide by the mass of car 2. i dont know what to do plz help

2. Jan 21, 2012

### jmoser

sorry i wrote the wrong title

3. Jan 21, 2012

### tiny-tim

welcome to pf!

hi jmoser! welcome to pf!

(never make the first reply to your own question … it removes the question from the no-replies list! … if necessary, use the EDIT button instead )
just take it slowly …

i] what is total momentum before?

ii] what is total momentum after?

4. Jan 22, 2012

### jmoser

ok thanks ill remember that :) ok the total momentum before is 36252 all i did was mass times velocity and add both momentum for both and that is what i got and after the collision it is the same right?

5. Jan 22, 2012

### tiny-tim

hi jmoser!
that's right!
your english is difficult to understand

yes, the total momentum after is also 36252 …

so what is the speed?