kinetic energy/momentum conservation (rest mass energy)

Discussion in 'MCAT Discussions' started by IndyZX, Apr 30, 2004.

1. IndyZX 7+ Year Member

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when an atom shoots off an alpha particle during alpha decay, is kinetic energy or momentum conserved?

i say neither is conserved, what do you think?

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3. liverotcod Lieutenant Crunch 10+ Year Member

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I think it would be:
kinetic energy: no, because mass is being converted to kinetic energy
momentum: yes, because the nucleus will recoil in response to the alpha particle ejection.

4. IndyZX 7+ Year Member

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doesnt total mass increase? some of the weak nuclear force is coverted to mass i thought...

5. UCLAstudent I'm a luck dragon! 10+ Year Member

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Yes, I believe that this is correct.

6. liverotcod Lieutenant Crunch 10+ Year Member

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I'm not 100% clear... but this site is helpful. There is mass lost in alpha decay, probably because of the decrease in potential energy in the parent nucleus after the decay.

7. Nuel 10+ Year Member

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Mass is probably lost due to speed of these nuclear particles (dilation factor effect), especially electrons--decrease in potential energy which follows from increase in KE of the moving particles.

I think I just rambled nonsense here

8. Shrike Lanius examinatianus 10+ Year Member

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Everyone's got the right answer here (KE not conserved, because a massive particle is ejected; momentum conserved). Just wanted to point out: momentum is always conserved, as long as you're considering a closed system.

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