Is relative velocity confusing in multiple vector systems?

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Homework Help Overview

The discussion revolves around the concept of relative velocity in a scenario involving multiple vectors, specifically focusing on the interaction between the velocity of rain and the velocity of a woman running in the rain. Participants are examining the correctness of vector diagrams and the implications of vector addition in this context.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the accuracy of vector resolutions and the placement of angles in the diagram. There are discussions about how the velocity of the rain appears different from the woman's perspective compared to the ground's perspective. Some participants are exploring the implications of running against the rain on the perceived angle of the rain's velocity.

Discussion Status

The discussion is ongoing, with participants offering insights and clarifications regarding vector addition and the interpretation of relative velocities. There is acknowledgment of confusion regarding the relative velocity concept, and some participants have expressed gratitude for clarifying responses. However, there is no explicit consensus on the correct interpretation of the vectors involved.

Contextual Notes

Participants are navigating potential misunderstandings related to vector diagrams and the assumptions about the directions of velocities. There are references to external threads for further exploration of related problems, indicating a broader context of inquiry.

Hijaz Aslam
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Are the vectors resolved correctly? I get a different answer to this question(well my diagram itself is different). How can ##\beta## be greater than ##\alpha##?

Isn't it that here ##\alpha## should be in place of ##\beta## and ##\beta## in place of ##\alpha## and both ##V(rain,woman)## and ##V(rain)## should be in each others place?
 
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I believe that the diagram is wrong. The V(woman) vector should be transported to the right, starting at the tip of V(rain), and the sum should be constructed putting the end of V(woman) at the tip of V(rain). As the vectors of the picture seem to be to scale, the sum vector will lean to the right, clearly...
 
The speed of the rain in respect to ground vg is given by
v_g=v_rw+v_w

where v_rw is the speed of the rain in respect to the woman and v_w is the speed of the woman.
Take these as velocities (vectors) and this is what they have there.

If the woman runs against the rain, the horizontal component of the rain's velocity should be larger from the point of view of the woman than from the ground. The vertical component is not changed. So the angle is larger.
 
nasu said:
The speed of the rain in respect to ground vg is given by
v_g=v_rw+v_w

where v_rw is the speed of the rain in respect to the woman and v_w is the speed of the woman.
Take these as velocities (vectors) and this is what they have there.

If the woman runs against the rain, the horizontal component of the rain's velocity should be larger from the point of view of the woman than from the ground. The vertical component is not changed. So the angle is larger.

Yes, I was wrong in my post above... Imagining the rain falling vertically, running in any direction will result in the angle perceived by the runner growing more and more horizontal the faster he runs...
 
nasu said:
The speed of the rain in respect to ground vg is given by
v_g=v_rw+v_w

where v_rw is the speed of the rain in respect to the woman and v_w is the speed of the woman.
Take these as velocities (vectors) and this is what they have there.

If the woman runs against the rain, the horizontal component of the rain's velocity should be larger from the point of view of the woman than from the ground. The vertical component is not changed. So the angle is larger.
Oh yes. This relative velocity baffles me always :(

Nasu - thanks for your reply. Your answer cleared it. If you don't mind can you look into this problem in my thread ( https://www.physicsforums.com/threa...taining-multiple-vectors.777125/#post-4887266 ) Relative velocity catches me there too :( .
 

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