# Homework Help: Crash acceleration

1. Oct 30, 2008

### simplekin93

1. The problem statement, all variables and given/known data
A person drives his SUV into a concrete wall. The car was initially moving East at 12.5m/s and the hood crumples a distance of 1.2m during the crash. What is the acceleration of the car during the crash? (don't forget directions when dealing with acceleration)

I don't even know where to begin.

2. Oct 30, 2008

### Rake-MC

What constant acceleration formulae do you know?

3. Oct 30, 2008

### simplekin93

almost all of them, i was given a big formula sheet that we are allowed to use in the test.

4. Oct 30, 2008

### Rake-MC

So this is what we have:

initial velocity (12.5ms-1)
final velocity (0.0ms-1)
distance (1.2m)

What we need:

acceleration

What formula do you know that uses only these variables?

5. Oct 30, 2008

### simplekin93

Vf^2 = Vi^2 +2ad

6. Oct 30, 2008

### Rake-MC

Perfect! Now we just need to re-arrange that formula and solve for a!

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