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# A Level Mechanics Question watch

1. Hi I have a question I'm stuck with, any help would be appreciated.

Two hooks, A and B, are fixed to the ceiling. The distance AB is 2.5 m.

a) A particle, C, of mass 3kg is suspended from A and B by two light, inextensible strings. AC is 2 m and BC is 1.3 m. Calculate the tension in the strings,

b) The two strings are now replaced by a single string of length 3.3 m, which is threaded through a smooth ring attached to the particle. A horizontal force, P N, is applied to the particle so that it rests in the same position as before. Calculate the value of P and tension in the string.

I've done the first part. I used the cosine rule and then equated the horizontal and vertical forces. However I'm obtaining the wrong answer for b and can't spot my mistake. I've attached my diagram.

Attached Images

2. Without getting stuck in to all of the technical details - is it because you only have one T in your diagram? Should there not be the same T, pointing along the directions of both parts of the string from the ring?
3. (Original post by Pangol)
Without getting stuck in to all of the technical details - is it because you only have one T in your diagram? Should there not be the same T, pointing along the directions of both parts of the string from the ring?
Ok thank you, I understand that and will give it a go.
4. (Original post by tommy_lees)
Ok thank you, I understand that and will give it a go.
Thank you. With the two tension strings it works. Thanks for your help.

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