- #1
Dependent motion problem with ropes
- Thread starter theBEAST
- Start date
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- Motion
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Homework Help Overview
The discussion revolves around a dependent motion problem involving ropes, where participants are exploring the relationships between various lengths and their changes. The original poster expresses confusion regarding the setup of the problem and the placement of the datum.
Discussion Character
- Exploratory, Assumption checking, Mathematical reasoning
Approaches and Questions Raised
- Participants discuss the unknowns in the problem, specifically identifying them as A and C, while questioning how to eliminate another variable, B. There is a focus on understanding the dependencies between length changes and the use of calculus to analyze these relationships.
Discussion Status
The conversation is ongoing, with participants providing insights into the relationships between the variables and suggesting rearrangements of equations. There is acknowledgment of the role of derivatives in simplifying the problem, but no consensus has been reached on the overall approach.
Contextual Notes
Participants are navigating the complexities of the problem setup and the implications of constant values in their equations. The original poster's confusion about the datum and the dependencies indicates potential gaps in the problem's context.
- #2
gneill
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theBEAST said:
What are your two unknowns? Remember, you're looking for dependencies between certain length changes.
- #3
theBEAST
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gneill said:
I know it's A and C but I don't know how to get rid of B :S
- #4
gneill
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theBEAST said:
Here's your drawing with the distances labeled.
Your equation is:
L = SA - SB + 2SC
What you're looking for is the rate of change of SA with respect to a rate of change of SC. So rearrange your formula to have SA on the left and the rest on the right. Now, are you familiar with calculus (derivatives)?
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- #5
theBEAST
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gneill said:Here's your drawing with the distances labeled.
Your equation is:
L = SA - SB + 2SC
What you're looking for is the rate of change of SA with respect to a rate of change of SC. So rearrange your formula to have SA on the left and the rest on the right. Now, are you familiar with calculus (derivatives)?
Oh... I see, so if you take the derivative Sb and L are eliminated since they are constant?
- #6
gneill
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theBEAST said:
Yup.