Car collision, force exertion and impulse.

AI Thread Summary
In a car collision, the average force exerted on a passenger's head striking an unpadded dashboard is 48N for a duration of 3 milliseconds. If suitable padding is present, the impact duration increases to 0.6 seconds, which helps to spread the force over a longer time, reducing the average force experienced. The impulse, calculated as the product of force and time, remains constant in both scenarios, indicating that while the total change in momentum is the same, the longer impact duration with padding results in a significantly lower average force. Understanding the relationship between force, time, and impulse is crucial for calculating the potential reduction in injury severity. Proper calculations can demonstrate how increased impact duration leads to safer outcomes in collisions.
TheAkuma
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Hello everyone, I have a question which I have no idea how to work out.

Question: During a collision between two cars, a passangers head strikes an unpadded dashboard with an average force of 48N. This force is exerted for 3x10-3s. If suitable padding had been present the impact would have lasted for 0.6s. Explain with calculations how this would reduce injuries in collisions.


The only equation I know that involves force is F=mXa, but I don't think that's even relevant to this question.



I don't know how to attempt this question as my teacher never gave us a question like this before. If you could give me some feedback that would be awesome.
 
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Well, here's the situation: the passenger's head is moving at some particular velocity. Then it collides with the dashboard, which slows it down to zero velocity. That much is always true, no matter how much padding is present on the dashboard. The effect of the padding is to spread out that slowdown over a longer period of time. Think about this: what effect does that have on the average force?
 
diazona said:
Well, here's the situation: the passenger's head is moving at some particular velocity. Then it collides with the dashboard, which slows it down to zero velocity. That much is always true, no matter how much padding is present on the dashboard. The effect of the padding is to spread out that slowdown over a longer period of time. Think about this: what effect does that have on the average force?

Sorry about not understanding but I still don't get how to calculate it all out. I know that the 0.6s is better as there is more time for the force to spread out as the head hits the dashboard. But I just don't know how to use calculations for this question.
 
You have the correct formula. Can you explain to me what the a stands for? Explain it in terms of speed then try to link it to your question.
 
Two more formulas you should find helpful here are:
J = F*dt = dP
Where F is the average force. Keep in mind that in both collisions, the impulse the head will be providing to the dashboard will be the same.
 
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