## YumYum247 one year ago someone help me!!! :)

1. YumYum247

2. YumYum247

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3. YumYum247

But how do i find the angle?????

4. YumYum247

@welshfella can you help me?!?!?!? O_o

5. YumYum247

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6. IrishBoy123

lotta drawings here, all look different. is there a scan or link to question?

7. YumYum247

8. IrishBoy123

why do you think the asnwer is 25N ???

9. YumYum247

it looks pretty obvious.....doesn't it....do you want me to show you how i got it???

10. IrishBoy123

yes pls show!

11. IrishBoy123

question 10N down 8N up how is that 18N down shouldn't it be 2N down?!

12. YumYum247

try to find the hypotenuse like that....

13. IrishBoy123

forget about hypoteneuses for the minute do you have a book answer if it is 18N down the answer is 32.33N if it is 2N as it should be the answer still isn't 25N do you know the law of cosines??? cos that makes this really easy

14. YumYum247

why your using cosine here doe????

15. IrishBoy123

"law of cosines" ring a bell ?!?!

16. YumYum247

yes but first tell me what does the hexagon means on the diagram????

17. IrishBoy123

isn't that the shape of the body? i have never seen it before! i am about to post a few drawings. bear with me

18. IrishBoy123

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19. YumYum247

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20. IrishBoy123

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21. IrishBoy123

if the diagram is right, this is how you do it you must resolve the 17N force in the x and y directions

22. YumYum247

is it ....C^2 = A^2 + B^2-2abCos45???

23. IrishBoy123

yeah! do you actually know that law?!?! cos it makes life really easy this easy http://www.wolframalpha.com/input/?i=%2817%5E2+%2B+2%5E2+-+2%2817%29%282%29cos+135%29%5E%281%2F2%29

24. YumYum247

yah....well kinda...ok but please tell me under what scenario do i use the sin law in questions such as these......or do we ever use the sin law in these type of questions?

25. YumYum247

because i haven't done a single question that uses sin law instead of cos.

26. IrishBoy123

you need to know more angles to use the law of sines, though it is a much easier rule to apply look at this https://gyazo.com/75c2ae6ed28fa5e3109a4e87a4775967

27. YumYum247

ok Thanks hun.....just one last thing.....to find the angle, we use sinA/a + SinB/b = SinC/c right???????????/

28. YumYum247

i meant sinA/a = SinB/b = SinC/c

29. IrishBoy123

yes, that is the law of sines but the question does not want the direction of the force, just its magnitude

30. IrishBoy123

i think we shoukd just resolve the 17N force in the x and y direction as i suggested.

31. YumYum247

yah but for some reason, the examples that i have also include the angle.....so my final answer would be like....suppose 50N (E70S)

32. YumYum247

but i think in our case the angle would be 45degree right??????

33. IrishBoy123

we can do the angle but using simple trig id's did you follow the drawing hwere the 17N is resolved in x and y directions, cos that is a few steps off getting us done.

34. IrishBoy123

the final angle will not be 45deg

35. IrishBoy123

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36. YumYum247

oh you sohcahtoa..

37. IrishBoy123

now you can use pythagoreas etc

38. YumYum247

ok so now i can apply the pythangorem theorem right....

39. YumYum247

ok Thanks alot... :)

40. IrishBoy123

forgive me for the impertenance (!!!) but did you follow the resolving of the 17N

41. IrishBoy123

17 cos 45 up, 17sin45 to the left

42. IrishBoy123

cool!

43. YumYum247

hey sorry, i went to take a d....p but yah so 17sin 45 will give me the angle on x-axis and 17cos45 will give me the angle on the y-axis????

44. YumYum247

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