# Vectors questionWatch

#1
A boat has a position vector of (2i+j) and a buoy has a position vector of (6i-4j) relative to fixed origin O.

b) Find the bearing of the boat from the buoy.

I've done part a), which was to find the distance of the boat from the buoy. The answer is square root of 41.

I keep getting 328 as the bearing but the answer says 303.
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8 months ago
#2
(Original post by dont know it)
A boat has a position vector of (2i+j) and a buoy has a position vector of (6i-4j) relative to fixed origin O.

b) Find the bearing of the boat from the buoy.

I've done part a), which was to find the distance of the boat from the buoy. The answer is square root of 41.

I keep getting 328 as the bearing but the answer says 303.
Neither of those is correct... though you are closer than the ‘actual’ one.
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quote
8 months ago
#3
(Original post by dont know it)
A boat has a position vector of (2i+j) and a buoy has a position vector of (6i-4j) relative to fixed origin O.

b) Find the bearing of the boat from the buoy.

I've done part a), which was to find the distance of the boat from the buoy. The answer is square root of 41.

I keep getting 328 as the bearing but the answer says 303.
Hmmm, that's not what I'm getting.
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8 months ago
#4
Best to draw a diagram showing where the boat and the bouy.

Now, the boat relative to the buoy, can you find that vector?

Then can you find the relevent angles to find your answer (using the "boat relative to the buoy" vector)?
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8 months ago
#5
(Original post by dont know it)
A boat has a position vector of (2i+j) and a buoy has a position vector of (6i-4j) relative to fixed origin O.

b) Find the bearing of the boat from the buoy.

I've done part a), which was to find the distance of the boat from the buoy. The answer is square root of 41.

I keep getting 328 as the bearing but the answer says 303.
This question came up on here yesterday. It's Edexcel new syllabus AS Exercise 11F Q8. The online solution bank shows that they have misguidedly worked out the bearing of the origin from the buoy rather than the bearing of the boat from the buoy, so 303 (or 303.7) is definitely wrong. But 328 is also wrong. Can I suggest that you show your working?
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#6
(Original post by old_engineer)
This question came up on here yesterday. It's Edexcel new syllabus AS Exercise 11F Q8. The online solution bank shows that they have misguidedly worked out the bearing of the origin from the buoy rather than the bearing of the boat from the buoy, so 303 (or 303.7) is definitely wrong. But 328 is also wrong. Can I suggest that you show your working?
Sorry, I actually got 321. I drew a triangle linking the boat to the buoy giving 4 units across and 5 units down. Using trig you can find one of the angles to make 38.7, 360-38.7=321.3.
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#7
Sorry, I actually got 321. I drew a triangle linking the boat to the buoy giving 4 units across and 5 units down. Using trig you can find one of the angles to make 38.7, 360-38.7=321.3.

(Original post by RDKGames)
Neither of those is correct... though you are closer than the ‘actual’ one.
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8 months ago
#8
(Original post by dont know it)
Sorry, I actually got 321. I drew a triangle linking the boat to the buoy giving 4 units across and 5 units down. Using trig you can find one of the angles to make 38.7, 360-38.7=321.3.
I agree with 321.
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#9
(Original post by old_engineer)
I agree with 321.
Thanks.
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