SAT physics question -- Flag on a bicycle being ridden in the wind....

Click For Summary

Homework Help Overview

The problem involves a girl riding a bicycle at a speed of 15 miles per hour due north, while a steady wind is blowing at 15 miles per hour from the east. The question focuses on the direction in which a flag mounted on the bicycle will be stretched due to the combined effects of the bicycle's motion and the wind.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss vector addition and the implications of wind direction, particularly noting that "from the east" indicates a westward direction for the wind. There is an exploration of drawing free body diagrams to visualize the forces acting on the flag.

Discussion Status

Some participants have recognized the correct interpretation of the wind's direction and have attempted to clarify the resultant vector's direction. There is an ongoing exploration of how the apparent wind affects the flag's position, with some guidance provided on visualizing the forces involved.

Contextual Notes

Participants are working under the constraints of a homework problem, which may limit the depth of their exploration. There is also a noted confusion regarding the representation of vectors and the apparent wind direction, which is being clarified through discussion.

YMMMA
Messages
156
Reaction score
10

Homework Statement


A girl is riding a bicycle at 15 miles per hour due north. A steady wind is blowing at 15 miles per hour from the east. A flag mounted on the bicycle will be stretched out toward the
(A) west (B) south (C) southwest (D) southeast (E) northeast

Homework Equations


Vector addition

The Attempt at a Solution


I drew an arrow pointing north then from its head i drew an arrow pointing east
I got E for the resultant vector. Is that right?
 
Physics news on Phys.org
YMMMA said:

Homework Statement


A girl is riding a bicycle at 15 miles per hour due north. A steady wind is blowing at 15 miles per hour from the east. A flag mounted on the bicycle will be stretched out toward the
(A) west (B) south (C) southwest (D) southeast (E) northeast

Homework Equations


Vector addition

The Attempt at a Solution


I drew an arrow pointing north then from its head i drew an arrow pointing east
I got E for the resultant vector. Is that right?
Welcome to the PF. :smile:

If the wind is "blowing from the east", the vector that represents it will not be pointing toward the east. Which way would it point?

Also, you should probably draw a free body diagram (FBD) of the flag to help you reason this problem out. Do you know how to do that? Show the forces of the two wind components on the flag...
 
Ahhhh, It says ‘from the east’ that means its directed west. Ugh, I should read well next time.
Thats how i draw the FBD. So, the answer is C.
 

Attachments

  • 487FEA8E-3819-4F80-904B-7E40F55CF107.jpeg
    487FEA8E-3819-4F80-904B-7E40F55CF107.jpeg
    7.2 KB · Views: 421
The correct answer is indeed C, but your vectors are still not quite right. You want the vectors to represent the wind forces on the flag. When the bike rider rides north, which was is the apparent wind blowing on the flag? :smile:
 
Oh, its west of south..
Do you mean the vector of the wind is from the tail of the north vector and directed west?
 
YMMMA said:
Oh, its west of south..
What's west of south?
YMMMA said:
Do you mean the vector of the wind is from the tail of the north vector and directed west?
I'm not sure what that means, sorry.

You have drawn the horizontal wind force vector correctly. Since the wind is coming from the east, the wind force from it is toward the west.

Since the bicycle is moving toward the north, the apparent wind force on the flag from that motion is pointing toward the ________
 
Sorry, I mean south of west.
I understood it. Now, I can imagine it pointing toward the south as a result of the motion.
Thanks a lot!
 
  • Like
Likes   Reactions: berkeman

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
13K
  • · Replies 20 ·
Replies
20
Views
3K
Replies
1
Views
2K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
3
Views
9K
  • · Replies 1 ·
Replies
1
Views
6K
  • · Replies 6 ·
Replies
6
Views
6K