Help with physics?

Eunos_Cosmo

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So I'm sort of struggling with this problem, anyone have some helpful ideas on what to do?

"Suppose that we could use the energy released
when 4 g of antimatter annihilates 4 g of
matter to lift a mass 1 km from the Earth?s
surface.
How much mass could we lift? Answer in
units of kg."

I was attempting to find the energy with e=mc^2 and using .004kg as the mass. Then I tried using work(energy)=mass*gravity*height to arrive at a mass, but my answer was incorrect. When I use .004kg for mass, I end up with 3.67e10, which isn't correct. Anybody got any ideas?

EDIT: I think the proper way is using the potential energy equation [energy=mass*gravity*height] after I have found energy from [e=mass*speed of light^2] Is this right?

Would the total energy released be from .004kg or from .008kg of matter?

Cmon...I know there are some Germans on here!
 
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Eunos_Cosmo

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7.347e10. I should have been using .008kg for the energy, not .004.
 

Blind_Io

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idk

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7.347e10. I should have been using .008kg for the energy, not .004.
Yep! Mass/Energy doesn't disappear. Whether it's matter or antimatter. Where should the "missing" 4g (or 4g*c^2 ) go? But well. U got it yourself :)
 
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