Galileo in spaaace: France's 'equivalence principle' satellite Earlier this week, France's snappily-named "Micro-Satellite à traînée Compensée pour l'Observation du Principe d'Equivalence", aka Microscope, rode a Soyuz lifter to orbit on a mission to " test the equivalence principle, which postulates the equality between gravitational mass and inertial mass". Legend has it that in around …
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"Galileo's suspicion was that all objects (in the same gravitational field) should fall at the same speed, irrespective of their mass, and he was eventually able to conclude that in a vacuum this would indeed be indeed be the case."
It wasn't really a suspicion that required observation to confirm or confute. It was based on reasoning alone, based on what would happen if a lighter (supposedly slower-falling) object were connected to a heavier (supposedly faster-falling) object.
The lighter object would retard the fall of the heavier object, so the speed of the pair would be a bit slower than that of the heavier. Yet by the same principle, the two connected objects would now constitute a single heavier object, so would be faster than both.
It's clearly impossible for both conclusions to be true, so the principle ("heavier objects fall faster") that leads us to them can't possibly be true.
Technically, no, since what you would be doing would be accelerating the earth towards the second mass, although this would lead to a larger combinrded.velocity. also, if the mass was large enough to exhibit this in any meaningful way, you'd have a much bigger problem on your hands, that I'm not sure even Bruce Willis could save us from with nukes...
"So... Technically a "heavier" (larger mass) object would be pulled towards the Earth with a larger force than a smaller mass, yes?"
Yes.
But the theory goes on to say that the inertia of the heavier mass is also greater and needs a larger force to experience the same acceleration as the smaller mass with its smaller force and smaller inertia. According to theory the difference in inertia exactly counters the increase in force, hence the large and small mass have the same acceleration. But is the theory true? So far all experiments have produced results consistent with the theory. The purpose of this experiment is to see if the theory holds with a more sensitive method.
Yes, quite. As we have F=m.a, and "a" (in this case g) is constant (for objects at the same height, and the same place*), F/m always is a constant.
So am I correct that they are trying to find if v(t)=v(0)+a.t, or substituted like v(t)=v(0)+(F/m).t is not holding at the extremes of mass (either way) where it becomes v(t)=v(0)+c.(F/m).t, where they would now have to find out where c is coming from?
*as we know that gravity is inversely proportional to distance from earth, composure of the mass it's moving over, etc.
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Force is mass times acceleration. While the force is smaller for a lighter object (correctly remembered), the inertia that has to be overcome is also smaller by the same amount. The mass of the accelerated small (compared to earth) object cancels out on both sides of the equation. This means the acceleration is the same for a heavy and a light object. The equivalence of heavy mass (causing the pull) and inert (correct word?) mass to be accelerated is the question we need to test here.
That's what I gather from this after a few pints...
Mine's the one with the slide rule
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