What is the Magnitude of Displacement for Various Directions and Distances?

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Homework Help Overview

The discussion revolves around calculating the magnitude of displacement in various scenarios involving vectors. The problems presented include a car's journey, a shopper's walk, a hiker's path, and a more complex walking route with multiple turns and angles.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss using the Pythagorean theorem for simple right-angle displacements and the cosine rule for angled displacements. There is uncertainty about which equations to apply for different scenarios, particularly in the last problem.

Discussion Status

Some participants are seeking clarification on the application of equations and whether to combine methods for the more complex problems. There is a mix of attempts to verify calculations and confusion about the resultant vectors, indicating an ongoing exploration of the concepts involved.

Contextual Notes

Participants express concerns about their understanding and performance in the subject, with one mentioning recent low homework grades. There is also a sense of urgency to grasp the material due to academic pressures.

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Okay i don't have the best physics teacher :-/ he often gets confused with what he's teaching and shows us the wrong thing...We have four problems for homework and I would just like one of you experts to check over it ;)

1. A car is driven 125 km due west, then 65 km due south. What is the magnitude of displacement? R^2=a^2 + b^2
R^2=125^2 + 65^2
R^2=19850
R=140.9 (about)
2. A shopper walks from the door of the mall to her car 250m down a lnae of cars, then turns 90 degrees to the right and walks an additional 60m. What is the magnitude of the displacement of her car from the mall door?
R^2=a^2 + b^2
R^2=60^2 + 250^2
R^2=66100
R=257.1 (about)
3. A hiker walks 4.5 km in one direction, then makes a 45 degree turn to the right and walks another 6.4 km. What is the magnitude of her displacement?
R^2= a^2 + b^2 - 2ab COS(angle)
R^2= 4.5^2 + 6.4 ^2 -2(4.5)(6.4)cos45
R^2=20.25 + 40.96- 40.729
R^2=20.481
R=4.526 (about)
4. What is the magnitude of your displacement when you follow directions that tell you to walk 225 m in one direction, make a 90 degree turn to the left and walk 350 m, then make a 30 degree turn to the right and walk 125 m?
I'm not sure how to go about doing this one but what I DO know is
how the triangle looks and the angle measurements. I'm just not
sure what it is I'm supposed to be writing down. A hand please lol?
 
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...would I use the first or second equation? What about a combination of both? ...maybe its a trick question lol maybe its right there you just have to know what it is...
 
You could use both. Get the resultant magnitude (R1) from the first two directions. And then find the resultant (R2) from R1 and the 3rd vector.
 
thanks! is the rest of it right?
 
isnt the resultant vector 125? whoaaa...*confused*
 
To find the resultant magnitude I would use r2=a2+b2 rite? i don't know what youre talking about the next part that confuses me..3rd vector is 125 correct?
 
please someone help my gpa is plummeting thru tha ground I've made 2 awful homework grades recently: 71% and a 76%! :'(
 

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