Graphical Vector Problem (What are they asking for?)

  • #1
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"Graphical" Vector Problem (What are they asking for?)

Homework Statement


Here is the problem statement. I honestly don't understand what it is they are asking for? Do they want actual numbers? Am I supposed to measure the lengths with a ruler or something? I know it's easy once I interpret the question correctly :smile:



Doc-11_14_105_08PM-page-1.jpg


How would you interpret this one?
 

Answers and Replies

  • #2
LCKurtz
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Hey, that vector A in part (c) is bent. Must have a non-zero curl :tongue2:

Yup, that's what I would do. Draw them carefully, construct the corresponding parallelograms and figure out the alpha and beta by measuring to scale things. "Trace" them certainly suggests that.
 
  • #3
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Hey, that vector A in part (c) is bent. Must have a non-zero curl :tongue2:

Yup, that's what I would do. Draw them carefully, construct the corresponding parallelograms and figure out the alpha and beta by measuring to scale things. "Trace" them certainly suggests that.

Haha! :rofl: Thanks LCKurtz! Don't quit your day job (assuming you have one!)!
 
  • #4
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By "graphical means" they mean for you to extend the vectors A and B so that the lengthened vectors form two sides of a parallelogram whose diagonal is C. You'll need to find the lengths of A and B with a ruler so that you can determine the values of [itex]\alpha[/itex] and [itex]\beta[/itex] so that [itex]\alpha[/itex]A + [itex]\beta[/itex]B = C.

For example, if you have to double the lengths of A and B to form the parallelogram, then [itex]\alpha[/itex] = [itex]\beta[/itex] = 2.

Your mileage may vary...
 
  • #5
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I must be an idiot. I cannot see a way to extend or shorten A and B such that C becomes the diagonal of the parallelogram. My brain keeps making B the diagonal since it is more intuitive to me.
 
  • #6
LCKurtz
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Don't forget that your coefficients of A and/or B may be negative so you also have to consider the opposite of A or B when making your parallelogram.
 

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