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M1 Vectors Help

Hello. How do you do part (c) in this question?

Reply 1
Original post by SirRaza97
Hello. How do you do part (c) in this question?



What thoughts of your own do you have?
Reply 2
Original post by Zacken
What thoughts of your own do you have?



I've worked out that at 10am, r = -2i and at 10:30am, r = -5i + 4j. All i know from that is that position vector of L has no J component. I don't know what else to do.
Reply 3
Original post by SirRaza97
I've worked out that at 10am, r = -2i and at 10:30am, r = -5i + 4j. All i know from that is that position vector of L has no J component. I don't know what else to do.


Right, so now set L's position vector as r = ai

You know that at time 10:30, the position vector of L is south-west of the ship. Sketch a diagram to represent this. Does that help?
Original post by SirRaza97
I've worked out that at 10am, r = -2i and at 10:30am, r = -5i + 4j. All i know from that is that position vector of L has no J component. I don't know what else to do.


OHHHHH!!!! i did this question, make sure you have a good diagram and keep the significance of South West in mind
Reply 5
Original post by Big white
OHHHHH!!!! i did this question, make sure you have a good diagram and keep the significance of South West in mind


Original post by Zacken
Right, so now set L's position vector as r = ai

You know that at time 10:30, the position vector of L is south-west of the ship. Sketch a diagram to represent this. Does that help?


I'm not sure what the significance of south west is actually. Has it got to with the i and j vectors being the same? I really have no idea.
Reply 6
Original post by SirRaza97
I'm not sure what the significance of south west is actually. Has it got to with the i and j vectors being the same? I really have no idea.


South west means parallel to the vector (i + j).
Original post by SirRaza97
I'm not sure what the significance of south west is actually. Has it got to with the i and j vectors being the same? I really have no idea.


Think in terms of angles :tongue:
Reply 8
Original post by Big white
Think in terms of angles :tongue:


45 degree angle from vertical and horizontal components?
Reply 9
Original post by SirRaza97
45 degree angle from vertical and horizontal components?


Yes.

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