- #1
jackster18
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Homework Statement
How much would the rest energy of a 1.0 Kg mass cost at the typical utility rate of $0.60/ kWh?
Homework Equations
E=mc^2
The Attempt at a Solution
Heres what somone told me from another website:
"The rest energy of a mass is the energy calculated by E=mc^2 when the mass is at rest.
E = (3E8 m/s)^2 * 1kg = 9E16 J
1 kWh = (1000 J/s)(3600 s) = 3.6E6 J
Energy * Cost/Energy = Cost
(9E16 J) * (1 kWh / 3.6E6 J) * ($0.60 kWh) = 15 billion dollars"
but i don't understand the last part, where they multiply (9E16 J) * (1 kWh / 3.6E6 J) * ($0.60 kWh). The eprson said Energy * Cost/Energy = Cost, so wouldn't that just be (9E16 J)(($0.60 kWh)/(9E16 J))?