Finding an angle in the direction of displacement

Click For Summary
To find Frank's total displacement vector, his movements can be represented as coordinates: 5.8 km East (x), 9.1 km North (y), and 1.5 km West (negative x). This results in a net displacement of 4.3 km East and 9.1 km North. Using these coordinates, the angle can be calculated using the arctangent function, yielding approximately 63.4 degrees North of East. The discussion highlights the importance of adhering to specific formatting requirements for the answer, which may cause confusion among participants. Accurate mathematical calculations are essential for determining the correct angle of displacement.
ilovedeathcab
Messages
11
Reaction score
0
finding an angle in the direction of displacement (resolved)

Frank hikes 5.8 km East, 9.1 km North, and 1.5 km West. Find the direction of his total displacement vector. Give your answer in terms of degrees North of East. Make sure you do the following in your answer:

* DO NOT write out a description of your angle. The text "North of East" is not necessary.
* DO NOT put your answer in terms of "East of North". This will be marked as incorrect.
* DO NOT indicate units. We will assume degrees.
* make your answer correct within 0.2 degrees
* put your answer in a form like one of these:
o #.#
o ##.#
--------------------------------------------------------------------------
i tried and measured this, converting km to cm, and measured with protractor, and got 67 degrees north of east. then i tried again, because my measurements were off, but it wouldn't accept 69 degrees. can't find what i am doing wrong (??)
 
Last edited:
Physics news on Phys.org


ilovedeathcab said:
Frank hikes 5.8 km East, 9.1 km North, and 1.5 km West. Find the direction of his total displacement vector. Give your answer in terms of degrees North of East. Make sure you do the following in your answer:

* DO NOT write out a description of your angle. The text "North of East" is not necessary.
* DO NOT put your answer in terms of "East of North". This will be marked as incorrect.
* DO NOT indicate units. We will assume degrees.
* make your answer correct within 0.2 degrees
* put your answer in a form like one of these:
o #.#
o ##.#
--------------------------------------------------------------------------
i tried and measured this, converting km to cm, and measured with protractor, and got 67 degrees north of east. then i tried again, because my measurements were off, but it wouldn't accept 69 degrees. can't find what i am doing wrong (??)

Try considering the distances in terms of x, y coordinates (I'd recommend East = x positive, North = y positive). Find the final position relative to the start point (0,0). You now have a right triangle, use that to find the angle mathematically.

I'm not sure I understand why there all the restrictions on description of the angle. Traditional compass directions consider North to be 0º, East to be 90º, for what it's worth.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 19 ·
Replies
19
Views
8K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
Replies
4
Views
3K
  • · Replies 38 ·
2
Replies
38
Views
8K
Replies
3
Views
1K