This is referring to the equation E = mc^2 .
Jump onto a pile of antimatter.
E = mc[sup]2[/sup] for an 80-kg man works out to 7.2x10[sup]18[/sup] joules of energy. Gasoline has a higher-heating-value of 35 megajoules per liter, so this the equivalent of burning 205 million cubic meters of gasoline (a cube 589 meters on a side).
No one man can come close to putting out that kind of energy by direct physical action. A 2-gigawatt power plant (e.g. Hoover dam)would have to operate for 114 years to put out that much electrical energy.
“No one man can come close to putting out that kind of energy by direct physical action.”
What if you made clones of the man, such as c copies of him?
What’s c? Speed of light? If c is expressed in Planck units, then c=1, and my answer is unchanged. 
It sounds like the question you actually would like to have answered is “how much mechanical work can one man perform in his lifetime?”
You could bench press Hyperion (a moon of Jupiter) once or run from the Earth to the Sun and back 90,000 times.
As a comfortable estimate, human basal metabolism is about 80 Watts, and we can double that by doing hard work. How about an average, then, over one’s lifetime of 120 Watts? A 70 year lifetime gives roughly 74,000 KWh.
In practice, I can pedal a stationary bicycle with a generator connected to it and power a small tv set.
This would release twice as much energy, since the antimatter weighs just as much.
Only if the antimatter equals the person jumping on it in mass. You’d want half the jumper’s mass in antimatter.
Considering the law of conservation of energy, I’d guess that such a feat is impossible.
A man’s gotta eat, you know. 'Specially when bench-pressing moons of Jupiter.
Yeah, I learned either from school or some nerdy Isaac Asimov book that energy can’t be created. All the energy there ever will be already exists.
Good point. He didn’t say, so I assumed an excess of antimatter.
And then we could burn the half a man left over that didn’t get annihilated and get a bit more energy!
In an interview about the Lance Armstrong mess, one of the cyclists mentioned they had to eat 8,000 calories a day just to break even during the Tour de France.
Well, mostly I was answering from the point of view of how to release the energy contained in the body. Having released that amount of energy, I wasn’t going to worry about whether any additional energy was also released.
In reality, jumping onto a pile of antimatter wouldn’t result in anywhere near 100% conversion anyway. As soon as the first few grams (maybe even micrograms) reacted, both the person and the pile would be converted to high-energy plasma moving away from each other at very high speeds.
You can create energy from matter and vice-versa though (E = mc2), but then mass/matter is a property of energy, so it is really the same thing unless new matter can somehow be created from nothing.