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Calculating force of collison

  • Thread starter h9376w
  • Start date
  • #1
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This isnt 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 travelling at a constant speed of 50mph

or

a 2000kg vehicle travelling 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 havent actually got any of these factors)

Please Help :eek:

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
CAF123
Gold Member
2,902
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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.
 
  • #3
2
0
ok, so that would probably work.......

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

:)
 
  • #4
CAF123
Gold Member
2,902
88
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, [tex] Ft = m(v-u). [/tex] 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 [Broken])
 
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