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, [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 )

 

[Nickie]

I understand your curiosity about this problem. In order to calculate the force of collision, we need to consider both the mass and velocity of the objects involved. In this case, we have two scenarios: a 1500kg vehicle traveling at 50mph and a 2000kg vehicle traveling at 30mph.

First, let's calculate the kinetic energy of each vehicle using the formula KE = 1/2mv^2, where m is the mass and v is the velocity.

For the 1500kg vehicle: KE = 1/2(1500kg)(50mph)^2 = 93750000 J

For the 2000kg vehicle: KE = 1/2(2000kg)(30mph)^2 = 90000000 J

From this calculation, we can see that the 1500kg vehicle has a greater kinetic energy than the 2000kg vehicle. However, this does not necessarily mean that it will have a greater impact with a stationary object.

To determine the force of collision, we also need to consider the stopping distance of each vehicle. This is because the longer the stopping distance, the longer the time it takes for the vehicle to come to a complete stop, and therefore the force of collision will be reduced.

So, in order to accurately compare the force of collision between the two scenarios, we need to know the stopping distance of each vehicle. Without this information, we cannot make a definitive conclusion.

In conclusion, while we can calculate the kinetic energy of each vehicle, the force of collision also depends on the stopping distance, which we do not have in this theoretical scenario. Therefore, we cannot accurately determine which vehicle would have a greater impact with a stationary object.