## Dealing with mass, acceleration and velocity

1. The problem statement, all variables and given/known data
Problem: A person wearing a seatbelt can withstand an acceleration of -0.030 m/s2. How thick should barriers be to safely stop a car that hits a barrier at 110 km/h?

2. Relevant equations
F=m*a?

3. The attempt at a solution
I so far have no attempt. I do not know what sort of formula can be used or what type of problem it is ie. constant velocity, displacement, friction so on. The sort of help that I need is a possible formula you might know of or even what kind of problem this is.
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 Blog Entries: 4 Recognitions: Gold Member I think the key formula is, with a=acceleration, v=initial speed, t=time and s=distance, $$s = \frac{1}{2}at^2 + vt$$ Assume the barrier applies a constant deceleration.
 Thank you Mentz114. That is very helpful! I'll try the problem using that formula now. Thanks again!

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