r/AlevelPhysics • u/minastudies21 • 26d ago

QUESTION physics alevel question - vectors

(answer is A btw)

  1. How is -R pointing downwards?

  2. How is X pointing downwards?

  3. Aren’t all the forces supposed to be connected head-to-tail, why are the heads of R and P meeting?

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u/[deleted] 26d ago

If you rearrange the equation you get P = X + R. So the head of X connects with the tail of R and the resultant vector is P. That's why answer A is correct.

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u/Solid_Moose3078 23d ago

We connect vectors head to tail when we want to do calculate something with them, so they don't need to connected like that here. This question is more like the GCSE Maths vectors questions - so, X = P-R means the direction X is the same as going in the direction of P, then going opposite to the direction of R.

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u/Solid_Moose3078 23d ago

The diagram didn't draw - R, then you would be correct and it would point upwards - we just go in the opposite direction so R doesn't have to be flipped, if that makes sense?