Solving a Rowing Kinematics Problem: Finding the Rate of the Current

Click For Summary

Homework Help Overview

The problem involves kinematics related to rowing, specifically determining the rate of the current affecting a rower's speed upstream and downstream. The original poster seeks assistance in solving the problem after encountering difficulties with their initial ideas.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss setting up equations based on the relationship between speed, time, and distance for both upstream and downstream rowing. There is mention of defining variables for the current's speed and the distances traveled in each direction.

Discussion Status

Some participants have provided guidance on formulating equations to represent the problem, while others reflect on their own challenges with the problem-solving process. There is a recognition of different approaches, but no explicit consensus has been reached.

Contextual Notes

The original poster expresses frustration with their attempts, indicating a potential struggle with the complexity of the problem. There is also a light-hearted exchange regarding simplifying problem-solving strategies.

Omid
Messages
181
Reaction score
0
A man who can row 4 miles per hour in still water finds that he can row upstream in 7 and 1/2 hours a distance which requires 2 and 1/2 hours to row downstream. Find the rate of the current.

When I saw the problem at once I had dozens of ideas to solve it but all of them failed.
Can you give me some hints ?

Thanks
 
Physics news on Phys.org
The most direct way would be setting up the known equations and solve for them.
You have two unknowns, the speed of the current and the distance travelled.
You also have two linearly independent equations:
-The 'speed*time=distance' equation for going upstream
-The 'speed*time=distance' equation for going downstream

The speed when going upstream/downstream is just the speed of the man minus/plus
the speed of the current.
 
Let the current be v. Speed upstream is 4-v and the distance rowed in 7 and 1/2 hours is d= (4-v)(15/2). Speed downstream is 4+v and the distance rowed in 2 and 1/2 hours is (4+v)(5/2). Since those distances are the same, set them equal and solve for v.
 
I was making the problem harder and harder by using relative motion and vectors, ... that's why I couldn't solve it.
I must remember to kiss ( Keep It Simple and Straight forward) , as you did here, when solving physics problems.

Thank you very much
 
You mean it's not "Keep it simple, STUPID"? That's what people always tell ME!
 
HallsofIvy said:
You mean it's not "Keep it simple, STUPID"? That's what people always tell ME!


:biggrin: :biggrin: :biggrin: :biggrin: :biggrin:
 

Similar threads

  • · Replies 25 ·
Replies
25
Views
4K
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 6 ·
Replies
6
Views
3K
Replies
1
Views
2K
Replies
2
Views
1K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 20 ·
Replies
20
Views
3K