Eb6 What is the plane’s total displacement

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Discussion Overview

The discussion revolves around calculating the total displacement of an airplane trip consisting of three legs with specified distances and directions. Participants explore methods for visualizing the trip and calculating displacement, including both graphical and mathematical approaches.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Participants discuss the feasibility of using technology like Desmos for graphing the trip versus drawing it by hand.
  • There is a clarification regarding the direction of the third leg of the trip, with some participants questioning whether "53 degrees south of west" should be interpreted as "S 53 degrees W" or "S 37 degrees W."
  • One participant suggests setting up a coordinate system to calculate vector components for each leg of the trip, providing specific calculations for the first two legs.
  • Another participant provides a calculation for the third leg's components, leading to a proposed final position based on the cumulative vector addition.
  • Participants express uncertainty about the correct interpretation of directional angles and the terminology used in describing the legs of the trip.

Areas of Agreement / Disagreement

There is no consensus on the interpretation of the directional angle for the third leg of the trip, with competing views presented. The discussion remains unresolved regarding the correct terminology and its implications for the calculations.

Contextual Notes

Participants reference the need for clarity in definitions and the potential for confusion in interpreting angles, which may affect the calculations of displacement.

karush
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An airplane trip involves three legs, with two stopovers,
The first leg is due east for 620 km;
the second leg is south- east ($$45^\circ$$) for 440 km
and the third leg is at 53$$^\circ$$ south of west, for 550 km
a. the first thing is to see if there is a way to graph this either with Desmos or someother online grapher
b. What is the plane’s total displacement
ok I know that we need to calculate its magnitude as well as direction for a complete discription.
 
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karush said:
An airplane trip involves three legs, with two stopovers,
The first leg is due east for 620 km;
the second leg is south- east ($$45^\circ$$) for 440 km
and the third leg is at 53$$^\circ$$ south of west, for 550 km
a. the first thing is to see if there is a way to graph this either with Desmos or someother online grapher
b. What is the plane’s total displacement
ok I know that we need to calculate its magnitude as well as direction for a complete discription.

Why bother trying to use technology to graph it when it's so easy to draw by hand?

Also, $53^{\circ}$ south of west, do you mean $S\,53^{\circ}\,W$ or $S\,37^{\circ}\,W$?
 
Prove It, "53 degrees S of W" is, properly, "S 37 degrees W". "S 53 degrees W" would be "53 degrees W of S".

Karush, The simplest thing to do is to set up a "coordinate system" and calculate the components of the vectors. Set up a coordinate system with the initial point as origin, (0, 0), positive x-axis to the right (east) and positive y-axis upward (north).

"An airplane trip involves three legs, with two stopovers,
The first leg is due east for 620 km;"
That would be to the right so we are now at (620, 0)

"The second leg is south- east ([FONT=MathJax_Main]45[FONT=MathJax_Main]∘) for 440 km"
The second leg has components (440 cos(-45), 440 sin(-45))= (220sqrt(2), -220sqrt(2)) so we are now at (620+ 220sqrt(2). -220 sqrt(2))= (931, -311).

"and the third leg is at 53[FONT=MathJax_Main]∘ south of west, for 550 km
"53 degrees south of west" is 180- 53= 127 degrees from the positive x-axis (east) so this motion would be (550 cos(127), 550 sin(127))= (-331, 439). We wind up at (931- 331. -311+ 439)= (600, 128).

"a. the first thing is to see if there is a way to graph this either with Desmos or someother online grapher"
Its really just a matter of drawing straight lines and measuring angles. Do have a protractor?
(Does anyone today know what a protractor is or have they gone the way or the slide rule?)

"b. What is the plane’s total displacement"
ok I know that we need to calculate its magnitude as well as direction for a complete discription."

The magnitude is sqrt(600^2+ 128^2) and the angle, measured from east, is 180+ arctan(128/600).
 
Prove It said:
Why bother trying to use technology to graph it when it's so easy to draw by hand?

Also, $53^{\circ}$ south of west, do you mean $S\,53^{\circ}\,W$ or $S\,37^{\circ}\,W$?

because I am making a pdf of these problemsand the third leg is at $53^\circ$
 
HallsofIvy said:
Prove It, "53 degrees S of W" is, properly, "S 37 degrees W". "S 53 degrees W" would be "53 degrees W of S".

karush said:
and the third leg is at $53^\circ$


I had a feeling, hence why I asked...
 
You had a feeling that Karush didn't know what it meant?
 

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