|MadSci Network: Physics|
Consider the forces on a metal bar held at each end by some sort of support. On it is a mass, placed anywhere but the centre. The physics says that the two supports will have different forces applied to them by the block (through the effects of gravity), and that when released, the block will fall and accelerate under gravity, the bar and mass remaining in the former horizontal position. However, if you imagine this mass to be replaced by some other force, say a charged particale is strapped to the bar, and an electic field applied to pull the charge (which is near massless!) downwards.....then you can see that the situation is the same as before in that different forces are to be found at the supports, but now when you realease the bar (and charge), surely it will rotate?! If this is so, then the forces on the supports cannot just be in the vertical direction, otherwise the bar, when released, will not rotate (as the forces on the supports are different, but now there is no mass to be accelerated). Could you please explain either the flaw in my logic, or the missing physics! Many thanks, Chris.
Re: Question about free fall versus rotating bodies.
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