# Net Force and Deacceleration

1. Oct 24, 2009

### Sky.Anthony

1. The problem statement, all variables and given/known data

A 58 kg person is in a head-on collision. The car's speed at impact is 13 m/s. Estimate the net force on the person if he or she is wearing a seat belt and if the air bag deploys.

For some reason, I can't seem to get the correct answer to this question... I have no idea where I am going wrong. According to the question, if a person is wearing a seatbelt, they deaccelerate over a distance of 1m.

2. Relevant equations

(Final Velocity)^2 = (Initial Velocity)^2 + 2*acceleration*distance
Force=mass*acceleration

3. The attempt at a solution

First off, I had to find the deacceleration over the distance of 1m:
(Final Velocity)^2 = (Initial Velocity)^2 + 2*acceleration*distance
0 = (13m/s)^2 + 2*acceleration*1m
acceleration= -84.5m/s^2

Using that acceleration to calculate net force...
F=ma
= (58kg)(-84.5m/s^2)
=-4901N

I put that answer into the system and it comes back wrong...

Help is appreciated. Thanks!

2. Oct 25, 2009

### look416

well it sound reasonable to me
but thinking back if a person wearing seatbelt should they move forward then move back ward?

3. Oct 25, 2009