If the meteorite was moving at 500 m/s before striking the car, what was the magnitude of its acceleration while stopping?

The solution would be like this for this specific problem:

a = v2r (formula for magnitude of acceleration)

a = 6.25 * 105 ms^-2

Use V^2 = Vo^2 + 2a (X - Xo)

We know that the meteorite travels at a speed of. 2m, but it stops moving so V^2 has a 0 value. Also, you’re told that Vo is 500 and Xo is 0.

0 = 500^2 + 2a (.2 - 0)

-250000 =.4a

a = - 625000. I thought that a should have been negative since it was slowing down, but it told me to change signs so a should be a = 625000 m/s^2