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Another Addition of Vectors question.

  • Thread starter Scooter I
  • Start date
  • #1
12
0

Homework Statement



Sudhir walks 0.40 km in a direction 60.0° west of north, then goes 0.50 km due west. What is his displacement?

Homework Equations



According to my textbook, the equations are:

Ax = A cos θ
Ay = A sin θ
Bx = B cos θ
By = B sin θ
θ = tan-1 opposite side/adjacent side

Source: http://www.jpopovich.com/file.php/19/phy_chap5.pdf on page 122.

The Attempt at a Solution



http://screensnapr.com/e/zuQNvk.png [Broken]

Click to see full image.

Both my answers are wrong according to my textbook. Can someone tell me why / explain to me?

The real answer: 0.87km at 77 degrees west
 
Last edited by a moderator:

Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
10
I think you mixed up adding the .5 west. It should go with the west component of the .4, which is the .35 to give you .85.

Keeping 2 digit accuracy in the work only gives you 1 digit accuracy in the final answer.
 
  • #3
116
1
You seem to have mixed up the x- and y-components for the vector A. You have the correct equations, but you wrote the x-component as the y-component and vice versa.
 

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