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Help with forces in action question

OCR a level

Hey all. I’m normally alright at doing these triangle of forces questions but this one has stumped me.

The question in the book (image below) does it one way which I don’t like so I tried to draw the diagram. Where am I cocking up?

Thanks

(Doesn’t allow me to upload. Hope you’re okay with links - https://imgur.com/a/15ikFct)
Reply 1
Original post by Olly5847558
OCR a level

Hey all. I’m normally alright at doing these triangle of forces questions but this one has stumped me.

The question in the book (image below) does it one way which I don’t like so I tried to draw the diagram. Where am I cocking up?

Thanks

(Doesn’t allow me to upload. Hope you’re okay with links - https://imgur.com/a/15ikFct)

your triangle isnt right angled and it would be more obvious to sketch the 25 degree angles a bit smaller as its isosceles 25-25-130. The simplest way is pretty much as the book does so perpendicular bisect of the 120N side to create two identical right triangles, then Tcos(25)=60, though you could also do the sin rule on the original isosceles triangle.
(edited 6 months ago)
Reply 2
Original post by mqb2766
your triangle isnt right angled and it would be more obvious to sketch the 25 degree angles a bit smaller as its isosceles 25-25-130. The simplest way is pretty much as the book does so perpendicular bisect of the 120N side to create two identical right triangles, then Tcos(25)=60, though you could also do the sin rule on the original isosceles triangle.

Managed to figure it out. Thanks though! I was being a stupid idiot thinking I could use SOHCAHTOA on a non right angled triangle! If anyone remotely cares here's how I did it: https://imgur.com/a/ujqB59I
Original post by Olly5847558
OCR a level

Hey all. I’m normally alright at doing these triangle of forces questions but this one has stumped me.

The question in the book (image below) does it one way which I don’t like so I tried to draw the diagram. ....


Can I ask why is it that you don't like the method presented in the book?
Reply 4
Original post by Eimmanuel
Can I ask why is it that you don't like the method presented in the book?

Not likely to think like this in the exam.

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