Rhys_M
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Hi,
In the question below i keep checking my working and can't find a mistake with my numbers so i'm assuming my method's flawed?
Thank you
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mqb2766
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The 625 should be 25. The magnitude of a is 5, so a^2 = 25.
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Rhys_M
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(Original post by mqb2766)
The 625 should be 25. The magnitude of a is 5, so a^2 = 25
But the vectors i'm adding to give the resultant are forces, so i need to equal it to the magnitude of the force, not acceleration, don't I?
(Using f=ma)
If not then why would they give me the mass?
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mqb2766
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Yes, missed the mass part. Just skim read the acceleration.
What does the model solution give?
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Rhys_M
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(Original post by mqb2766)
Yes, missed the mass part. Just skim read the acceleration.
What does the model solution give?
There's not a worked solution but the MS just says -7/3 and -3
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mqb2766
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-3 gives a force of magnitude 5. I guess -7/3 does the same, so your soln is correct, they;ve probably calculated witen the force has magnitude 5.
Note the -3 solution corresponds to a 3 : 4:5 triangle.
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Rhys_M
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(Original post by mqb2766)
-3 gives a force of magnitude 5. I guess -7/3 does the same, so your soln is correct, they;ve probably calculated witen the force has magnitude 5.
Note the -3 solution corresponds to a 3:4:5 triangle.
Thank you
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Rhys_M
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(Original post by Rhys_M)
Thank you
There's another question of the same type to which I also get a wrong answer VVVV
Do you think the book has a systematic error?
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mqb2766
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Not sure what the solution is, but your +10 isnt correct.
Sub the book answer and your corrected answer into the F = .. expression and you should be able to work out which is correct?
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