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## graphical method to find magnitude and direction

 Quote by xupe33jrm The force vector FA has a magnitude of 90.0 newtons and points due east. The force vector FB has a magnitude of 135 newtons and points 75° north of east. Use the graphical method and find the magnitude and direction of (a) FA - FB (give the direction with respect to due east) and (b) FB + FA (give the direction with respect to due west).
 Quote by isyndhrea based to my friend the graph is like this..?
for FA + FB, yes
 what graph is correct? is this problem use pythagorean theorem or component method?
 Blog Entries: 27 Recognitions: Gold Member Homework Help Science Advisor you can always use either the cosine formula or the component method (pythagoras only works for right-angled triangles … for general triangles you need the cosine formula)
 actually this is in my book .. FB-FA due to west and first i used component method which is x=90 y=0 x= 35 y=130 sum= x=125 y= 130 then i used pythgorean theorem
 . cosine formula?.. our professor did not teach about that..

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 Quote by isyndhrea actually this is in my book .. FB-FA due to west and first i used component method which is x=90 y=0 x= 35 y=130 sum= x=125 y= 130 then i used pythgorean theorem
(that's FB plus FA)

ah, i see what you mean …

yes, when you have the x and y components, you can then use the pythgorean theorem to give you the magnitude

(your answer should be "a magnitude of … newtons at an angle of … north of west")
 yes, when you have the x and y components, you can then use the pythgorean theorem to give you the magnitude (your answer should be "a magnitude of … newtons at an angle of … north of west")[/QUOTE] -is only one answer for this problem?..
 but the result is not 142 ang 67 degree.
 can you give me a specific formula? Attached Thumbnails
 Blog Entries: 27 Recognitions: Gold Member Homework Help Science Advisor that's 67° north of east, the question asks for the angle with respect to west

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 Quote by isyndhrea actually this is in my book .. FB-FA due to west and first i used component method which is x=90 y=0 x= 35 y=130 sum= x=125 y= 130 then i used pythgorean theorem
 so if i subtract the angle will be in north of west
 Hi guys..... I am new to his website and i dunno if i am using the correct place to ask my question Well the question is: When a vector is given say A: a i^+b j^+ck^ then how to find the angle between the vector and x-axis: y- axis; z-axis Thanq for ur time ......

 Quote by alex.hs Hi guys..... I am new to his website and i dunno if i am using the correct place to ask my question Well the question is: When a vector is given say A: a i^+b j^+ck^ then how to find the angle between the vector and x-axis: y- axis; z-axis Thanq for ur time ......
Hi alex.hs! Start a new thread about your question. Make sure you include an attempt along with it!

For starters, to find angle from x axis, think about taking an unit vector along x-axis, and use the concept of dot-product.