# Which car has the greater deceleration rate?

1. Sep 4, 2010

### theman12

1. The problem statement, all variables and given/known data
A 2500 kg truck collides into a 1250 kg car. Both cars were traveling the same speed in opposite directions. Which car has the greater deceleration rate?

2500 kg truck
1250 kg car
the same deceleration

2. Relevant equations

J=Pf-Pi=Ft

3. The attempt at a solution

i chose the same because a=v/t, and i thought theyd have the same delta v

2. Sep 4, 2010

### Filip Larsen

Re: Momentum/Impulse

Welcome to PF!

Assuming the cars stick together in the collision do you then know in which direction the combined wrecks travel right after collision? (hint: use momentum). From this information can you then conclude which car experience the greatest change in velocity and if this also corresponds to the greatest average deceleration? (hint: duration of collision is same for both cars, so greatest change in velocity equals greatest average deceleration).

3. Sep 4, 2010

### theman12

Re: Momentum/Impulse

the cars would probably travel in the direction of the truck, so the smaller car would have the greater change in velocity.