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Physics/The energy and mass

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Question
Hi,

According to Einstein's E=mc2

With an atomic bomb, as it explodes the energy within the mass is being spent (becoming less).

Therefore the equation states that as the speed of light remains constant, the mass must therefore become less.

But mass cannot become less as it cannot be created nor destroyed.

Do you see the contradiction ?

Thanks,
Janet

Answer
Before 1939 scientists didn't think mass could be created or destroyed.  Fission proved them wrong.  When the U235 atom is hit with a neutron it becomes U236.  That atom is unstable and splits into two pieces, such as Ba, Sr, Cs, I, etc., plus a couple of neutrons.  If you add up all those pieces the mass is less than the original.  The missing mass is converted into energy according to Einstein's equation E = mc^2.  There are other reactions that convert energy into mass, such a pair production.  

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Richard J. Raridon

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I can answer most questions in undergraduate physics courses, including electricity and magnetism, atomic and nuclear, mechanics and optics.

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I have taught undergraduate physics courses

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Sigma Xi, AAAS, SE section of APS

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BA in math, MA in physics, PhD in physical chemistry

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