Conical Pendulum question help please (1 Viewer)

[Elise8842]

Could someone show me how to do part c?

many thanks


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[dunjaaa]

(Forgot to add a 'so' after 'can')

 

[Elise8842]

Thank you so much !!!


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[Elise8842]

View attachment 30892 (Forgot to add a 'so' after 'can')

I had no idea when looking at part c... Would u minding telling what goes on in your head when you see it? What are the clues and hints you spot from the question that guides you to do it that way?


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[dunjaaa]

They made you find h and r in part (ii) and your final expression had no h's or r's but instead l's. From that, it is obvious that we had to eliminate them. Coincidentally, h, r and l are linked via Pythagoras. After using the pythagoras theorem, we find that the expression we obtain after multiplying out by T's is a quadratic (in terms of T). Only way to make T the subject was to use the quadratic formula. That was my thought process; hope that it explains things clearer

 

[Elise8842]

They made you find h and r in part (ii) and your final expression had no h's or r's but instead l's. From that, it is obvious that we had to eliminate them. Coincidentally, h, r and l are linked via Pythagoras. After using the pythagoras theorem, we find that the expression we obtain after multiplying out by T's is a quadratic (in terms of T). Only way to make T the subject was to use the quadratic formula. That was my thought process; hope that it explains things clearer

Ohhh now I see~~ that helps a lot! Thank you! :-D


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