? asked in Science & MathematicsPhysics · 9 years ago

Need help ASAP!!! Determine the MAGNITUDE of the bird watcher's (a) displacement and (b) average velocity.?

A bird watcher meanders through the woods, walking 0.219 km due east, 1.42 km due south, and 4.76 km in a direction 75.4 ° north of west. The time required for this trip is 1.616 h. Determine the MAGNITUDE of the bird watcher's (a) displacement and (b) average velocity.

I've tried this a couple of times but i seem to be getting the wrong answer.. i think it is to do with the magnitude ('+ve or -ve') .. thanks for any help!!

2 Answers

  • 9 years ago
    Best Answer

    Displacement and velocity are both vectors so only the initial and final points count, not distance traveled.

    Here is what you have:

    +0.219 km right (positive x axis)

    -1.42 km south (negative y axis)

    And 4.76 km north of west which must be broken down into x and y components:

    The x component is cosine of the angle (75.4) multiplied by 4.76, while the y component is sine of the angle multiplied by 4.76

    Since it is northwest the x component will be negative and y will be positive.

    Now you need to add your x components together and your y components together and draw it on a piece of paper (be careful with signs).

    Now using pythagoreans theorem (x^2 + y^2 = z^2) to find the total displacement.


    If you have to be in SI units (meters and seconds) divide displacement by 1000 and multiply time 1.616 by 3600).

    Then just solve for velocity

    Source(s): If anything is unclear, edit your question and let me know... I don't give solutions onY! Answers, I just provide the required inforation to allow them to be found.
  • 4 years ago

    West component of 3rd. leg = (cos 44) x 2.2, = 1.5825km. North component = (sin 44) x 2.2, = 1.52825km. (1.5825 - 0.3) = 1.2825km. west of origin, and (1.52825 - 0.75) = 0.77825km. north of origin. Displacement = sqrt. (0.77825^2 + 1.2825^2) = 1.5km., and angle = arctan (0.77825/1.2825) = 31.25 deg. N of W.

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