Conservation of linear momentum

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SUMMARY

The discussion centers on the conservation of linear momentum in the context of a perfectly inelastic collision between two cars. The equation m1*v1 + m2*v2 = (m1 + m2)v12 is correctly identified as applicable when the two objects stick together post-collision. This scenario results in a common speed for both cars after the collision due to the conservation of momentum principle, which dictates that the total momentum before the collision equals the total momentum after the collision. The clarification provided emphasizes that this equation is not valid for elastic collisions where objects bounce off each other.

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  • Understanding of linear momentum
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  • Familiarity with basic physics equations
  • Concept of conservation laws in physics
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jahlin
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Homework Statement



Two cars 1 and 2 moving against each other collides.There are no external forces acting on them.

Homework Equations



conservation of linear momentum:
m1*v1+m2*v2 =(m1+m2)v12


The Attempt at a Solution


I have solved the problem but my question is how come they have a common speed after the collision?I don't understand this part can someone clarify it please.
 
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The equation you wrote is the one used when the two objects stick together when they collide, so after the collision there is only one object with a mass of m1+m2. This is called a perfectly inelastic collision. You can't use that equation if the objects bounce off each other.
 
thanks a bunch mikelepore!
 

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