Magnitude and Direction, Canoe on River

  • Thread starter ap_physics
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  • #1

Homework Statement


A canoe has a velocity of 0.35 m/s southwest relative to the earth. The canoe is on a river that is flowing 0.65 m/s east relative to the earth. Find the velocity (magnitude and direction) of the canoe relative to the river.

The Attempt at a Solution


0.930985 is the magnitude.
Then I have no clue how to get the angle in terms of counterclockwise from east.

Thanks very much in advance!
 
Last edited:

Answers and Replies

  • #2
gneill
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Homework Statement


A canoe has a velocity of 0.35 m/s southwest relative to the earth. The canoe is on a river that is flowing 0.65 m/s east relative to the earth. Find the velocity (magnitude and direction) of the canoe relative to the river.

The Attempt at a Solution


0.930985 is the magnitude.
Then I have no clue how to get the angle in terms of counterclockwise from east.

Thanks very much in advance!
Hi ap_physics; Welcome to Physics Forums.

How did you arrive at an angle of 315 degrees for the canoe's velocity? I would have thought that "southwest" would be halfway between south and west.

Edit: I see you've edited your original so that the angles of the vectors are no longer shown. Perhaps you could just explain your approach to the problem?
 
  • #3
Well, I posted my attempt earlier, but it was wrong, and I was given the answer for the velocity by my teacher, as it was too complicated for our level. But, he says I can still find the angle. But, I don't know which formula to use.
 
  • #4
gneill
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20,829
2,807
Well, I posted my attempt earlier, but it was wrong, and I was given the answer for the velocity by my teacher, as it was too complicated for our level. But, he says I can still find the angle. But, I don't know which formula to use.
Okay, what have you learned so far about adding and subtracting vectors? Have you learned how to determine their angles from their x and y components?
 

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