1 dimensional elastic collision

  • #1
190
0
A 0.415-kg hockey puck, moving east with a speed of 2.65 m/s, has a head-on collision with a 0.910-kg puck initially at rest.
Assuming a perfectly elastic collision, what will be the velocity of each object after the collision?
=======
The solution is:

v ' (lighter puck) , v' (heavier puck) = -0.990, 1.66 m/s, respectively.

My question is, wouldn't the lighter puck be expected to have a higher velocity magnitude than the heavier puck following the collision?
 

Answers and Replies

  • #2
307
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For perfectly elastic collisions, kinetic energy is conserved.

[tex]K_i=K_1+K_2[/tex]
 
  • #3
190
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Ok, i made that assumption when solving the problem.

I'm asking conceptually, wouldn't the heavier object be expected to move with a smaller velocity magnitude?
 
  • #4
307
0
Ok, i made that assumption when solving the problem.

I'm asking conceptually, wouldn't the heavier object be expected to move with a smaller velocity magnitude?

Sorry, I didn't read your question properly :redface:

That will only be the case if the initial kinetic energy is divided equally between the two objects, i.e. when after the collision

[tex]\frac{1}{2}m_1v_1^2=\frac{1}{2}m_2v_2^2[/tex]

so that

[tex]\frac{m_1}{m_2}=\frac{v_2^2}{v_1^2}[/tex]
 
  • #5
190
0
Ah gotcha. Thanks for the help! :smile:
 

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