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mechanics bearing question

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 BCapture.PNG
(edited 2 years ago)
Reply 1
Hihi,
It might be worth checking your answer for part a!
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! :smile:
(edited 2 years ago)
Reply 2
Original post by xOutcast
Hihi,
It might be worth checking your answer for part a!
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! :smile:

tysm for this! I'm a bit confused though if my answer for A is incorrect - could you give me some guidance?
Reply 3
The issue is with the j component - probably just a typo/mental maths mistake I think!
Reply 4
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 :tongue:
Reply 5
Original post by kswales1
Ahhh is it meant to be 80j? i messed up the scale on my graph by accident :tongue:

Yep! Let me know what you get for your bearing when you get it and we can see if we match :biggrin:
Reply 6
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 :biggrin:

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?
(edited 2 years ago)
Reply 7
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 :smile:
Reply 8
Original post by xOutcast
Absolutely perfect. Beautiful diagram and answer in perfect form :smile:

Awesome, thank you so much for your help!!
Reply 9
Original post by kswales1
Awesome, thank you so much for your help!!

Pleasure! Best of luck with everything! :smile:

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