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M2 Modelling Circular Motion

I'm on q 6).

Up until now the questions have involved masses attached to strings attached to a point. So I've not had success with this question at all.

This is my thinking: The masses would want to fly off the turntable. I only say this because when you're on a roundabout that what it feels like. But because all the masses are the same it's equalled out so they can't but that's what causes the tension in the strings.

I found the distance of each mass from the centre and used that to find the acceleration of each mass. Then I used F = ma (same for each mass). And then I didn't have an iota of an idea.
The tension in the strings is what causes the centripetal force whose magnitude you've found. By symmetry, each mass will feel the same tension in each string. You merely need to resolve the centripetal force into two forces at right angles to each other which add vectorially to give the centripetal force.

It's just a bit of trig.
Original post by maggiehodgson
I'm on q 6).

Up until now the questions have involved masses attached to strings attached to a point. So I've not had success with this question at all.

This is my thinking: The masses would want to fly off the turntable. I only say this because when you're on a roundabout that what it feels like. But because all the masses are the same it's equalled out so they can't but that's what causes the tension in the strings.

I found the distance of each mass from the centre and used that to find the acceleration of each mass. Then I used F = ma (same for each mass). And then I didn't have an iota of an idea.


... and the resultant inward force is 2Tcos 45.
Original post by atsruser
The tension in the strings is what causes the centripetal force whose magnitude you've found. By symmetry, each mass will feel the same tension in each string. You merely need to resolve the centripetal force into two forces at right angles to each other which add vectorially to give the centripetal force.

It's just a bit of trig.



Yes, thanks. I've got it to work.

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