Elastic Collisions between two objects

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SUMMARY

The discussion centers on an elastic collision problem involving two siblings on ice, where one sibling has a mass of 52 kg and is initially at rest, while the other has a mass of 60 kg and approaches with a velocity of -4.9 m/s. The key equation for solving this problem is the conservation of momentum, represented as m1v1 + m2v2 = m1v1' + m2v2', where the primes denote post-collision velocities. The user initially calculated a relative speed of 4.55 m/s, which was incorrect, indicating a misunderstanding of the application of the conservation of momentum in elastic collisions.

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Flinze
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Homework Statement


You have an inertia of 52 kg and are standing at rest on an iced-over pond in your skates. Suddenly, your 60-kg brother skates in from the right with x component of velocity -4.9 m/s and collides elastically with you.

1. What is the siblings' relative speed after the collision?

Homework Equations


m1v1+m2v2=m1v1+m2v2

The Attempt at a Solution


WvlUmrX.png

This is part of my assignment online, and it when I plug in 4.55 m/s it says my answer is incorrect. I'm lost at this point.
Thanks in advance!
 
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Flinze said:

Homework Statement


You have an inertia of 52 kg and are standing at rest on an iced-over pond in your skates. Suddenly, your 60-kg brother skates in from the right with x component of velocity -4.9 m/s and collides elastically with you.

1. What is the siblings' relative speed after the collision?

Homework Equations


m1v1+m2v2=m1v1+m2v2
Has the above equation any information? It is a trivial identity.

Flinze said:

The Attempt at a Solution


WvlUmrX.png

This is part of my assignment online, and it when I plug in 4.55 m/s it says my answer is incorrect. I'm lost at this point.
Thanks in advance!
Relative with respect what?
The question is the relative speed of you and your brother after the collision.
 

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