Force & Motion Homework: How to Calculate Force from Restricted Motion

[tjbateh]

Homework Statement

A car traveling at 48 km/h hits a bridge abutment. A passenger in the car moves forward a distance of 53 cm (with respect to the road) while being brought to rest by an inflated air bag. What magnitude of force (assumed constant) acts on the passenger's upper torso, which has a mass of 40 kg?

Homework Equations

The Attempt at a Solution

Can somebody please help me with an approach to this type of problem.

 

[rock.freak667]

Try using conservation of energy. The car has kinetic energy and when it hits, work is done in moving the passenger 53cm into the air-bag.

 

[tjbateh]

Hmm, we have not gone over kinetic energy in class yet. I'll read up on it, and post an approach and see if it's right.