Which Vehicle Has a Greater Impact Force: 1500kg at 50mph or 2000kg at 30mph?

[h9376w]

This isn't officially a homework question, just a problem/discussion that has arisen at work...

so, basically we are looking to find out which would have a greater impact:-

a 1500kg vehicle traveling at a constant speed of 50mph

or

a 2000kg vehicle traveling at a constant speed of 30mph

we are basing this on impact with a stationary object with no movement, eg a solid wall.

Now i know that F = MA, but with the speed being constant then surely there would be no acceleration?

is there anyway we can calculate this with just the information provided? or does stopping time/distance have to get involved (as this is just a theoretical question, we haven't actually got any of these factors)

Please Help

 

[CAF123]

Well, you could calculate the impulse (or change in momentum) of the cars assuming when they hit the wall, they stop. If you define positive x right, then the impulse will be in the negative x direction, same direction as the force exerted by the wall. To find the magnitude of the force exerted on the cars by the wall requires their time of contact.

 

[h9376w]

ok, so that would probably work...

can you explain how i would go about working that out?

:)

 

[CAF123]

ok, so that would probably work...

can you explain how i would go about working that out?

:)

Have you come across the concept of impulse and momentum?
Use the relation, $$Ft = m(v-u).$$ This is essentially F = ma but inputting a kinematic relation which describes constant acceleration. As I said before, with the given data you can only compute the quantity Ft, known as impulse.
See here : http://en.wikipedia.org/wiki/Impulse_(physics )