Settting up force problem with only mass and velocity provided

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SUMMARY

The discussion focuses on calculating the net force experienced by a 60 kg person during a head-on collision at a speed of 15 m/s, with the deceleration occurring over a distance of 1 m due to seat belt and airbag deployment. The primary equation used is F=ma, but the challenge lies in determining the acceleration from the given initial and final velocities. The relevant kinematic equation vf² = vi² + 2aΔx is identified as essential for solving the problem, allowing for the calculation of acceleration before applying F=ma.

PREREQUISITES
  • Understanding of Newton's second law (F=ma)
  • Familiarity with kinematic equations
  • Knowledge of initial and final velocity concepts
  • Basic grasp of deceleration and distance in physics
NEXT STEPS
  • Learn how to apply kinematic equations to solve for acceleration
  • Study the relationship between force, mass, and acceleration in real-world scenarios
  • Explore examples of collision physics and safety mechanisms like airbags
  • Investigate the implications of deceleration distances in vehicle safety design
USEFUL FOR

This discussion is beneficial for physics students, automotive safety engineers, and anyone interested in understanding the dynamics of collisions and the forces involved in vehicle accidents.

Zontar
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Homework Statement



A 60kg person is in a head-on collision. The car's speed at impact is 15 m/s. Estimate the net force on the person if they are wearing their seat belt and the air bags deploy. When these two events occur, the passenger decelerates over a distance of 1 m.

Homework Equations



This is a force problem so I reasoned I would need to use F=ma. Below explains other equations I try.

The Attempt at a Solution



This is the way I saw it. I need "F" and I have "m", but they gave me a velocity instead of an acceleration. Although I need an acceleration, I don't know how to set up the kinematics problem (I greatly struggle with this part of each problem) and I try all different things that don't make sense. So I have V_f = 0 m/s while V_i = 15 m/s but all the equations I tried still have an unknown "time" or "distance", which I don't understand how to extrapolate out of the problem. Would I use D_i as 1 m and D_f as 0 m since it decelerates over a distance of 1 m?
 
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You are first looking for your acceleration, so you are going to ignore the F=ma until you know "a"

https://www.physicsforums.com/showthread.php?t=110015
find the equation that had distance, acceleration, and a starting velocity, and a final velocity

vf^2=vi^2+2aΔx
 

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