# mechanics bearing question

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#1
Hi,

I'm trying to part b of this question. I think I've found the vector BH in part A to be -60i + 70j but honestly I'm not entirely sure and I have no clue where to start for part B
Last edited by kswales1; 1 month ago
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1 month ago
#2
Hihi,
Then for the second part, I suggest drawing a sketch. Then you can use some knowledge of trigonometry to work out some angles (from B to H), and then the bearing. Remember the bearing is the angle relative to north, goes clockwise, and is 3 digits. For example, an angle of 87 degrees clockwise is 087. An angle of 93 degrees anticlockwise will be 267. Let me know how you get on!
Last edited by xOutcast; 1 month ago
1
#3
(Original post by xOutcast)
Hihi,
Then for the second part, I suggest drawing a sketch. Then you can use some knowledge of trigonometry to work out some angles (from B to H), and then the bearing. Remember the bearing is the angle relative to north, goes clockwise, and is 3 digits. For example, an angle of 87 degrees clockwise is 087. An angle of 93 degrees anticlockwise will be 267. Let me know how you get on!
tysm for this! I'm a bit confused though if my answer for A is incorrect - could you give me some guidance?
0
1 month ago
#4
The issue is with the j component - probably just a typo/mental maths mistake I think!
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#5
(Original post by xOutcast)
The issue is with the j component - probably just a typo/mental maths mistake I think!
Ahhh is it meant to be 80j? i messed up the scale on my graph by accident
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1 month ago
#6
(Original post by kswales1)
Ahhh is it meant to be 80j? i messed up the scale on my graph by accident
Yep! Let me know what you get for your bearing when you get it and we can see if we match
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#7
(Original post by xOutcast)
Yep! Let me know what you get for your bearing when you get it and we can see if we match
I've attached a photo of the diagram I'm using to make it easier to explain my working -
Using the trig, I can find the θ angle, but what I'm actually trying to find is the ∝ angle because the bearing goes clockwise. So I used tanθ = opp / adj to find θ (tan^-1 (60 / 80) = 36.87). Then I subtracted this value from 360 to find the actual bearing. 360 - 36.87 = 323.13 ≈ 323. Is this correct?
Last edited by kswales1; 1 month ago
0
1 month ago
#8
(Original post by kswales1)
I've attached a photo of the diagram I'm using to make it easier to explain my working -
Using the trig, I can find the θ angle, but what I'm actually trying to find is the ∝ angle because the bearing goes clockwise. So I used tanθ = opp / adj to find θ (tan^-1 (60 / 80) = 36.87). Then I subtracted this value from 360 to find the actual bearing. 360 - 36.87 = 323.13 ≈ 323. Is this correct?
Absolutely perfect. Beautiful diagram and answer in perfect form
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#9
(Original post by xOutcast)
Absolutely perfect. Beautiful diagram and answer in perfect form
Awesome, thank you so much for your help!!
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1 month ago
#10
(Original post by kswales1)
Awesome, thank you so much for your help!!
Pleasure! Best of luck with everything!
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