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Why is the answer positive? (M1)



For X I got - 8√3 [24cos30 - 40sin60] :s-smilie:
hello.png124.6KB
answer gives in magnitude. you only give negative values whe they are in the opposite plane. e.g north + south -, or even north east and south west
Original post by Adorable98
For X I got - 8√3 [24cos30 - 40sin60] :s-smilie:


You just resolved as if x were to the left ~ (40sin60 - 24cos30) would be the correct working, but you know it should be positive anyway, so if you end up with a negative answer you can usually assume it's wrong :3
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Adorable98
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Original post by Kawaii289
answer gives in magnitude. you only give negative values whe they are in the opposite plane. e.g north + south -, or even north east and south west


Original post by Asuna Yuuki
You just resolved as if x were to the left ~ (40sin60 - 24cos30) would be the correct working, but you know it should be positive anyway, so if you end up with a negative answer you can usually assume it's wrong :3


I'm a bit confused, aren't we supposed to always assume that 'north' and 'east' is positive?:s-smilie:
(edited 7 years ago)
Original post by Adorable98
I'm a bit confused, aren't we supposed to always assume the 'north' and 'east' is positive?:s-smilie:


You are generally supposed to assume so yes, as it's the positive on the x/y axes, however you didn't follow that in your answer. It should be ~

X + 24cos30 = 40sin60 (equating positive and negative forces)

X = 40sin60 - 24cos30 (rearranging for X)

You just had an error with which way round to resolve your forces :cute:
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Adorable98
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Original post by Asuna Yuuki
You are generally supposed to assume so yes, as it's the positive on the x/y axes, however you didn't follow that in your answer. It should be ~

X + 24cos30 = 40sin60 (equating positive and negative forces)

X = 40sin60 - 24cos30 (rearranging for X)

You just had an error with which way round to resolve your forces :cute:


I see!! Thank you!!:biggrin:
Original post by Adorable98
I see!! Thank you!!:biggrin:


No problem :five:

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