Needs clarity on this displacement vector diagram

Click For Summary
The discussion centers on confusion regarding a displacement vector diagram related to a problem involving a river current and a boat's velocity. The vertical arrow beside NA is clarified to represent the vertical component of displacement, which is 5 km, while the label of 3 km is identified as a possible typo. Participants confirm that the provided diagram is mislabeled and that the user's own sketch of the displacement vector is accurate. The conversation emphasizes the importance of correctly interpreting the components of the diagram to solve the problem effectively. Overall, the key takeaway is the need for clarity in vector diagrams to avoid misunderstandings in physics problems.
Chijioke
Messages
14
Reaction score
3
Homework Statement
How far from his destination
Relevant Equations
The trigonometric ratios of acute angles in a right angled triangle:
SOH CAH TOA
IMG_20230831_042607.jpg

The problem is actually a solved example
IMG_20230901_042351.jpg

My attention is focused in understanding the displacement vector diagram as it has to deal with question (iv).
I have no problem understanding the velocity vector sketch below:
velocity vector.png


As you can see ND is the velocity of the river current due East and NE is the velocity of the boat supposed the man chooses to go Northward.
Here comes another sketch for the velocity
displacement vector original.png

I am confused about the sketch because
a. I don't understand what the vertical arrow beside NA meant.
b. the 3km, is what? Is the displacement of the river or what? If it is, how was obtained because I know from the wording of the problem nothing like that was given. what was given 3 kmhr-1, which the displacement of the river. From the solving as it in the book I thinking that the 5km
IMG_20230901_043519.jpg


As I showed here
displacement vector (1).png

Please help my understanding. Thank you.
 

Attachments

  • IMG_20230901_042351.jpg
    IMG_20230901_042351.jpg
    43.8 KB · Views: 93
  • IMG_20230901_042351.jpg
    IMG_20230901_042351.jpg
    43.8 KB · Views: 83
  • IMG_20230901_043519.jpg
    IMG_20230901_043519.jpg
    15.6 KB · Views: 96
  • IMG_20230901_042351.jpg
    IMG_20230901_042351.jpg
    43.8 KB · Views: 98
Physics news on Phys.org
Chijioke said:
I am confused about the sketch because
a. I don't understand what the vertical arrow beside NA meant.
b. the 3km, is what? Is the displacement of the river or what? If it is, how was obtained because I know from the wording of the problem nothing like that was given. what was given 3 kmhr-1, which the displacement of the river. From the solving as it in the book I thinking that the 5km
You are understandably confused because the diagram provided in the solution is mislabeled. The vertical arrow beside NA must represent the vertical component of the displacement which is given as 5 km. The label 3 km is either a typo or the drawing is pasted from a different problem. Your drawing of the displacement vector is correct.
 
  • Like
  • Informative
Likes Lnewqban and Chijioke
kuruman said:
You are understandably confused because the diagram provided in the solution is mislabeled. The vertical arrow beside NA must represent the vertical component of the displacement which is given as 5 km. The label 3 km is either a typo or the drawing is pasted from a different problem. Your drawing of the displacement vector is correct.
I may still have question concerning this but let go and think. Thank you.
 
Chijioke said:
I am confused about the sketch because
a. I don't understand what the vertical arrow beside NA meant.
The river can't be made narrower: the man still has 5 km separating him from the opposite shore.
It must be a typo.
 
If have close pipe system with water inside pressurized at P1= 200 000Pa absolute, density 1000kg/m3, wider pipe diameter=2cm, contraction pipe diameter=1.49cm, that is contraction area ratio A1/A2=1.8 a) If water is stationary(pump OFF) and if I drill a hole anywhere at pipe, water will leak out, because pressure(200kPa) inside is higher than atmospheric pressure (101 325Pa). b)If I turn on pump and water start flowing with with v1=10m/s in A1 wider section, from Bernoulli equation I...

Similar threads

Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
934
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 19 ·
Replies
19
Views
8K
  • · Replies 38 ·
2
Replies
38
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 12 ·
Replies
12
Views
774