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

AI Thread Summary
When a car hits a wall, both the car and the wall experience equal force due to Newton's Third Law. However, the car undergoes a significant change in momentum, while the wall remains stationary, resulting in zero impulse for the wall. The discussion emphasizes that the wall is often treated as immovable, simplifying the analysis by assuming it has infinite mass. Thus, while the forces are equal, the effects differ due to the wall's inability to move. This highlights the importance of assumptions in physics problems involving collisions.
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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