A positively charged meteorite Zapyu (no such thing, but this is a thought experiment) is falling towards Earth. After it has reached a certain speed (say, v), God decides to show who's boss --- He switches off Zapyu's gravitational field (as God only can). Whap ! Zapyu's gravitational mass also goes to zero. Since Earth now exerts no pull on Zapyu, it continues to fall, but with uniform speed v. God smiles smugly at all who watch. .
Wait, though ! Along comes the Devil, who decides to show some muscle, just to keep his vote-bank intact. Whing ! He switches on a strong upward electric field to slow down/stop Zapyu's fall.
Now speak, O wise ones. Will the Devil succeed or won't he ? If he does, it means Zapyu still has inertial mass (since the external force retards its motion) although no gravitational mass, and the equivalence principle goes for a six. If he doesn't, Zapyu's i-mass has also vanished, the e-principle holds and both God and Einstein sigh in relief.
Well ?
2006-09-18
03:46:57
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5 answers
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asked by
Problem Child
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Physics