Do the i and j components cancel out? (Vectors & forces)

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jojo55
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Howdy .

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Size:  28.3 KBDo the i and j components cancel each other out when dividing or is something else happening in the above? (Using F = ma).
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xOutcast
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If you factorise out 5 out of the bottom, you'll notice the 4i + 3j cancel:
 \frac{4i+3j}{20i+15j} = \frac{4i+3j}{5(4i+3j)} = \frac{1}{5}
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jojo55
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(Original post by xOutcast)
If you factorise out 5 out of the bottom, you'll notice the 4i + 3j cancel:
 \frac{4i+3j}{20i+15j} = \frac{4i+3j}{5(4i+3j)} = \frac{1}{5}
Thank you. That makes sense .
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RDKGames
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Dividing vectors …. :eek:
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davros
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(Original post by RDKGames)
Dividing vectors …. :eek:
Didn't like to say anything, but that was my reaction when I saw it!

Wonder if this comes from a textbook or a mark scheme? Seems like a good case for reintroducing capital punishment
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DFranklin
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Had a similar reaction, but at the same time if I'm being honest what I'd do in practice is so similar (in practical terms, not notational) that it felt hypocritical and churlish to complain too loudly.
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davros
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(Original post by DFranklin)
Had a similar reaction, but at the same time if I'm being honest what I'd do in practice is so similar (in practical terms, not notational) that it felt hypocritical and churlish to complain too loudly.
I think the problem is that "it only works when it works" if you know what I mean. In all other circumstances it's a horrible abuse of notation, and while you and I would know what's intended I think there's a real danger of someone new to the topic seriously misunderstanding what the valid vector operations are.
Last edited by davros; 3 months ago
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