Which will experience a greater force when a car hits a wall?

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Homework Help Overview

The question discusses the forces experienced by a car and a wall when the car collides with the wall, specifically whether one experiences a greater force than the other. The context involves Newton's laws of motion, particularly the third law.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of Newton's third law, questioning the assumptions about the wall's immovability and the nature of impulse experienced by both the car and the wall.

Discussion Status

Some participants have noted the equal forces experienced by both the car and the wall due to Newton's third law, while others are analyzing the implications of momentum change and the assumptions made regarding the wall's mass and motion.

Contextual Notes

There is a discussion around the simplifying assumption that the wall is immovable, which influences the interpretation of the forces involved in the collision.

niveda
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Homework Statement


The question is asking when a car hits a wall, will the car or the wall experience the greater force.
2. Homework Equations

The Attempt at a Solution


I believe it's the equal force because of Newtons 3rd law
 
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niveda said:
I believe it's the equal force because of Newtons 3rd law
Correct.
 
Analysing the Car, there is a large change in momentum of the car (Impulse acts on it) and if we analyse the wall, the initial velocity was zero and the final velocity is also zero..so Impulse must be zero.
Car has more impact than the wall. You are right that the Third law of Newton beholds here. I think the question might be asking about the impact?
 
Lokendra1799 said:
Analysing the Car, there is a large change in momentum of the car (Impulse acts on it) and if we analyse the wall, the initial velocity was zero and the final velocity is also zero..so Impulse must be zero.
Car has more impact than the wall. You are right that the Third law of Newton beholds here. I think the question might be asking about the impact?
When we see a question with a casual statement like "a car hits a wall", we reflexively invoke the simplifying assumption that the wall is immovable in order to concentrate on presumably more interesting aspects of the problem. Our assumption is equivalent to assigning an effectively infinite mass to the wall or at least to whatever the is holding the wall in place.

While the impulse that the wall experiences must be identical to what the car experiences thanks to Newton III, the results in terms of motion must be interpreted in light of our assumptions: We don't expect any finite force integrated over finite time to cause an infinite mass to move.
 

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