Solving Vectors Question: Wind Direction & Velocity

  • Thread starter Thread starter AquaAqua
  • Start date Start date
  • Tags Tags
    Vectors
AI Thread Summary
A user seeks help with a physics problem involving wind direction and velocity while traveling east at different speeds. The problem requires constructing two vector triangles to analyze the wind's effect at speeds of 4.0 km/h and 8.0 km/h. Participants emphasize that the solution involves relative velocities rather than distances, and the user is encouraged to redraw their diagram correctly. Clarification is provided that the wind's direction is not strictly north or northeast, but rather needs to be determined based on the vector analysis. The discussion focuses on simplifying the problem through proper diagramming and understanding of vector relationships.
AquaAqua
Messages
3
Reaction score
0
Hey, I am new to the forum, but I've seen peoples help here and some of it is really good, but i have a question that i just don't get...

"A person traveling eastward at the rate if 4.0kmhr-1 observes that the wind seems to blow directly from the north after doubling his speed the wind appears to come from the north east, determine the direction of the wind and its velocity."

I tried drawing it on a graph but i got lost , i don't know what to do, and I am sure its really easy to...
any help?
 
Physics news on Phys.org
Welcome to PF!

HeyHey AquaAqua! Welcome to PF! :smile:
AquaAqua said:
"A person traveling eastward at the rate if 4.0kmhr-1 observes that the wind seems to blow directly from the north after doubling his speed the wind appears to come from the north east, determine the direction of the wind and its velocity."

As you've probably guessed, you need two vector triangles to solve this …

one has sides of lengths w (for the wind) and 4.0, and you know the directions of two of the sides …

the other has sides of lengths w (for the wind) and 8.0, and again you know the directions of two of the sides …

and you can simplify matters by putting the two triangles together, since the "wind" side is the same direction and length for each. :wink:
 


tiny-tim said:
HeyHey AquaAqua! Welcome to PF! :smile:


As you've probably guessed, you need two vector triangles to solve this …

one has sides of lengths w (for the wind) and 4.0, and you know the directions of two of the sides …

the other has sides of lengths w (for the wind) and 8.0, and again you know the directions of two of the sides …

and you can simplify matters by putting the two triangles together, since the "wind" side is the same direction and length for each. :wink:

Hey tiny tim, thanks for your help, but I am a bit physics retarded and I'm still not completley getting it...

attached an image of what i think i need to do?
can you maybe clarify?
BIG THANKYOU
 

Attachments

  • physics.png
    physics.png
    3.6 KB · Views: 427
Hey AquaAqua! :smile:

First, where did 12 come from? The two speeds east are 4 and 8. :wink:

Second, if w is meant to be the unknown speed Vwg of the wind relative to the ground (the same in both cases), then it isn't vertical (North).

Try again! :smile:​
 
Hey Tiny-Tim

,because it implies his journey at now8kmhr-1 from the point he was at (whiich was 4km from the origin...

So is it a 3d diagram?
hint, pretty please :D
 
Hey AquaAqua! :smile:
AquaAqua said:
because it implies his journey at now8kmhr-1 from the point he was at (whiich was 4km from the origin...

ah, no, the distances don't matter at all in a question like this.

This question is about relative velocities, and all you need is the velocities (ie, their magnitudes and directions) themselves.

The question says "after doubling his speed", which as you say is 8 kmhr-1.
So is it a 3d diagram?

No, it's two 2D diagrams stuck together … still 2D! :wink:

Your original diagram was the right idea, you've just labelled it wrong.

Redraw it, with w (the velocity of the wind relative to the ground) not from the north or north-east. :smile:
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Relative Wind Problem (Modern Engineering Mathematics, 5th)
Replies
3
Views
2K
Find the velocity of the wind relative to the boat
Replies
6
Views
1K
Roundtrip by Plane: Understanding Wind & Velocity Effects
Replies
26
Views
2K
To find the relative velocity of the wind as seen from a car
Replies
1
Views
1K
Finding the direction and velocity of wind using vectors question
Replies
1
Views
4K
To find the true velocity of wind from relative velocity
Replies
8
Views
2K
Vectors and Two Dimensional Motion
Replies
16
Views
2K
Velocity of wind based on the shape of a smoke trail
Replies
16
Views
2K
SAT physics question -- Flag on a bicycle being ridden in the wind....
Replies
6
Views
2K
Total work of a directional wind on a mailman
Replies
5
Views
1K

Hot Threads

Recent Insights

Back
Top