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Quote from: Geezer on 07/09/2011 07:35:54Quote from: JP on 06/09/2011 17:57:13I think what the poster might be describing (though the question was worded in a confusing manner) is that you appear weightless when in orbit. But you don't need to be in orbit. To become weightless, all you need to do is jump so that your feet are no longer in contact with anything.Whilst you are accelerating upwards you weigh more. At the top of the jump you weigh the same and only on the way down do you start to weigh less. It's got nothing to do with your feet touching the floor. It's all to do with acceleration in space-time.
Quote from: JP on 06/09/2011 17:57:13I think what the poster might be describing (though the question was worded in a confusing manner) is that you appear weightless when in orbit. But you don't need to be in orbit. To become weightless, all you need to do is jump so that your feet are no longer in contact with anything.
I think what the poster might be describing (though the question was worded in a confusing manner) is that you appear weightless when in orbit.
Quote from: MikeS on 07/09/2011 08:20:43Quote from: Geezer on 07/09/2011 07:35:54Quote from: JP on 06/09/2011 17:57:13I think what the poster might be describing (though the question was worded in a confusing manner) is that you appear weightless when in orbit. But you don't need to be in orbit. To become weightless, all you need to do is jump so that your feet are no longer in contact with anything.Whilst you are accelerating upwards you weigh more. At the top of the jump you weigh the same and only on the way down do you start to weigh less. It's got nothing to do with your feet touching the floor. It's all to do with acceleration in space-time.Not really. You are literally "weightless". It's only possible to "weigh" something when it is in contact with something else. You do weigh more while your legs are accelerating your mass and your feet are still in contact with the ground, but as soon as they leave the ground, you are weightless.
Mike,Wikipedia isn't always correct. The g in W=mg is constant which means that W must be proportional to mass, but it clearly is not. If you stand on a scale and bend your knees, your weight varies substantially.
Surely W=mg is just a way of knowing the weight of an object without actually 'weighing' it.
Weight is a measure of the force that local gravity exerts on something.So, while W=mg, g isn't a constant.Currently I weigh about 700 N, but if I moved to the moon, I would weigh about a sixth of that.If I moved upstairs I would weigh slightly less than I do here.