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# 3 forces in equilibrium help? watch

1. I have been attempting to do Question 2 (attached below) and have not been able to get Y = 5N after many attempts. I have watched a YouTube video (attached below) and then tried to answer the question using their technique. My workings are also attached below, so you can identify any errors that I have made along the way.

All help will be greatly appreciated!

Question 2:

My working:

2. The first thing I spotted was that -X cos 60 and + X sin 60 don't "cancel out".
3. That's exactly what I thought too.

I think it was that in the video's example the angle was 45, which is the rare occasion where the sine and cosine of the angle are the same.

However I do not see how I can find out Y when I do not know the value of X
4. (Original post by x0diak)
That's exactly what I thought too.

I think it was that in the video's example the angle was 45, which is the rare occasion where the sine and cosine of the angle are the same.

However I do not see how I can find out Y when I do not know the value of X
really? you missed something very big!
It's very short, fill in the missing angles i.e. between Y and X, you should notice something.
5. I still can't get Y to equal 5

Can you show me the full working and indicate where I went wrong please?
6. (Original post by x0diak)
I still can't get Y to equal 5

Can you show me the full working and indicate where I went wrong please?
You've resolved it correctly, but what followed is incorrect (xsin60 is the same as xcos30 but not the same as xcos60).

Re-arrange your first line to make x the subject of the formula (make x in terms of y) (it might help to know that cos60 = 0.5). Substitute x into your second equation. Take 10 to the other side, factorise the LHS by taking out y and find y.
7. Thank you SO much! You are an absolute life saver!!!
8. (Original post by x0diak)
Thank you SO much! You are an absolute life saver!!!
No Problem

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