Recent content by piisexactly3

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    Steel ball bearing in a magnetic field

    You can also find an explanation for the mutiple choice answers a few pages on in the mark scheme. It mentions how the field is non-uniform and so the ball bearing moves to where the density of the field is greater. It's starting to make some sense as far as my limited knowledge allows me.
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    Steel ball bearing in a magnetic field

    Ah here is the mark scheme http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_AS_2009_MS.pdf
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    Steel ball bearing in a magnetic field

    Thanks for the help so far. I have posted a link to the original question from an Olympiad paper, Q7, to remove ambiguity. http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_AS_2009_QP.pdf
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    Steel ball bearing in a magnetic field

    Ok so it now seems that an induced current is caused by a change in magnetic field across a given charge not a current. I think I have misinterpreted the original question in assuming that the ball bearing has been in the described position since the beginning of time. If that were the case...
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    Steel ball bearing in a magnetic field

    A change in magnetic field across a current right?
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    Steel ball bearing in a magnetic field

    induced emf is covered in the syllabus but that's it.
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    Steel ball bearing in a magnetic field

    I seem to be unable to confirm to myself what's really going here. Basically, we have a rectangular shaped magnet with north and south at opposite ends. A steel ball bearing is placed to the left of the magnet where it is equidistant from the north and south ends. Consequently, a force...
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    Power supplied holding a mass suspended in air

    Ok but hold 50 kilos out in front of you and tell my why its tiring but no work is being done?
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    Power supplied holding a mass suspended in air

    A problem I thought would be very simple, but can't seem to get very far with. Taking equations from textbook: Fv = P . Nope because velocity is 0 however power cannot be 0. Using suvat: W = Fs , s = ut + .5gt^t , therefore P = Fgt/2 , this seems like the equation for how power would...
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    Harnessing kinetic energy from impact of rain water

    I read in a science magazine that you would be able to generate more energy by collecting a mass of water and tipping it through a turbine than from generating energy from the impact of that mass of water as individual raindrops. Now this may simply be to do with the technology we have that...
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    Maximum angular velocity from a swing carousel

    Sorry I appreciate your time but I can't understand how 3) (x is the circumference and l is a radius) and 4) are true and how my formula is wrong and I can't understand points 2) and 5). Sorry again.
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    Maximum angular velocity from a swing carousel

    Ok here's my attempt at setting up an equation of motion with time. I going to define the variable x, as the distance across the circumference of the quarter circle the passenger travels as the centripetal force throws them ourwards across this path. The other variable is time t. The angular...
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    Maximum angular velocity from a swing carousel

    Ok well for now I will try to get through this with plain algebra. After correcting and refining my equations, I've come to the conclusion that the angle theta can be no larger than such a value that mg/cosθ could exceed T. In other words the maximum value for theta is θ=〖cos〗^(-1) mg/T ...
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    Maximum angular velocity from a swing carousel

    Does anyone how I can draw up and post free body diagrams? It would help me respond to the last two replies with much better clarity.
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    Maximum angular velocity from a swing carousel

    The problem is to find out the maximum angular velocity that the swing carousel can spin at before the chain holding the passenger breaks. The maximum tension that the chain can withstand is known (T). The radius from the centre of the ride to the chain when stationary is known (r). The...
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