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# Easy Scalars and Vectors AS Physics Question watch

1. Came up on CGP Revision Guide, not sure if it's a typo.

"Jemima is chasing a mechanised rabbit. She follows it for 50m south east, and then a further 80m west before catching it. By drawing a scale diagram, show that when Jemima catches the rabbit her displacement is 57m on a bearing of 218 degrees".

Ok, so I drew one, and I got displacement = square root of 50sin45^2 + (80-50cos45)^2 = 57m.

Then I got bearing = 180 + tan^-1 ([80-50cos45] / 50sin45) = 180 + 52 = 232, which doesn't equal 218 degrees. What gives?

Thanks.
2. (Original post by Teenage Hype)
Came up on CGP Revision Guide, not sure if it's a typo.

"Jemima is chasing a mechanised rabbit. She follows it for 50m south east, and then a further 80m west before catching it. By drawing a scale diagram, show that when Jemima catches the rabbit her displacement is 57m on a bearing of 218 degrees".

Ok, so I drew one, and I got displacement = square root of 50sin45^2 + (80-50cos45)^2 = 57m.

Then I got bearing = 180 + tan^-1 ([80-50cos45] / 50sin45) = 180 + 52 = 232, which doesn't equal 218 degrees. What gives?

Thanks.
I don't see anything wrong with your working. I think the author mistook the other angle to find the bearing.

218 - 180 = 38 deg

52 + 38 = 90 deg.

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