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  • How do I get the most mileage from an electric motor with gears?

    Suppose that I have vehicle that has electric motor and a six speed gear box.

    If I'm driving at 40 mph, would I get the most distance by:

    A) putting the vehicle in the highest gear and keeping the RPM count low, or

    B) setting the gear so that the RPM count would be the closest to the motor's maximum efficiency.

    Note that for an Internal Combustion Engine (ICE) you would get the most distance by using the highest gear and keeping the RPM count as low as possible. (Option A)

    Electric motors are different in that the are most efficient when they are running at 75% - 90% of their maximum RPM count, so I think that the answer should be Option B.

    Is that correct? Can anyone explain why one option would be better than the other for an electric motor?

    4 AnswersAlternative Fuel Vehicles10 years ago
  • Can I play an xbox 360 game that I bought in America on a console that I bought in France?

    My sister is visiting me in Florida from France, and I want to be able to give her some xbox 360 games for Christmas. If I did give her some games, will she be able to play them on her xbox 360 that she bought in France?

    Or is there some (pain in the neck) protection system that will not allow it to work?

    4 AnswersXbox1 decade ago
  • How easy is it to make hydrogen at home?

    I would love to buy one of those hydrogen powered ENV bikes, but the problem is where do I get the hydrogen from. One option is to make it myself, but I wonder how easy or practical this is, and what are the costs.

    8 AnswersEnvironment1 decade ago
  • Can an x-ray machine really detect explosive gels?

    The government's latest action to make air travelers feel safer is to force passengers to put all of their liquids and gels into a plastic bag and screen it separately from the rest of the x-rayed gear.

    Does that really make any difference? Do explosives look that different from toothpaste in the x-ray machine?

    3 AnswersChemistry1 decade ago
  • Does gravitational time dilation occur to objects in free fall?

    Wikipedia says that "Gravitational time dilation (GTD) is a consequence of Albert Einstein's theories of relativity [...] a clock at a different gravitational potential is found to tick at a different rate than one's own clock."

    “clocks which are far from massive bodies (or at higher gravitational potentials) run faster, and clocks close to massive bodies (or at lower gravitational potentials) run slower.”

    Is this due to the fact that the higher clock is simply further away from the earth than my clock, or because it experiences less pull from gravity?

    If two objects were released from different heights (so were both in free fall), would they have the same GTD because they are not experiencing any effect of the gravity, or would they have different GTD because they are at different heights (i.e. gravitational potentials) from the earth?

    What about objects in orbit? They are constantly accelerating (i.e. their vector of movement is changing) but do they experience GTD?

    2 AnswersPhysics1 decade ago