Solve Substitution Problem: Homework Equation v2=2v1

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Homework Help Overview

The discussion revolves around a substitution problem involving the relationship between two velocities, v1 and v2, where v2 is defined as twice v1. The original poster presents an equation that includes distances and times, aiming to solve for v1.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to manipulate the equation involving distances and velocities but expresses confusion regarding the order of operations. Some participants question the addition of fractions and suggest reviewing algebraic principles.

Discussion Status

Participants are engaged in clarifying algebraic concepts and providing supportive feedback. There is an acknowledgment of the original poster's struggle with the calculations, and some guidance has been offered regarding the addition of fractions.

Contextual Notes

The original poster indicates they are new to the forum and are taking an online physics course, suggesting a learning context that may involve additional constraints or challenges.

henrbp29
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Homework Statement



d1/d2 + d2/v2 = 0.500km/v1 + 3.50km/2v1 = 0.250h

Homework Equations



v2 = 2v1

The Attempt at a Solution



The answer is 9.00km/h but I keep coming up with 5.33. I know this is simple algebra but I am missing something in the order of operations.

0.500km/v1 + 3.50km/2v1 = 0.250h

4.00km/3v1 = 0.250h

4.00/(0.250h)(3) = v1

v1 = 5.33 ??
 
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[tex]\frac{a}{b}+\frac{c}{d}\neq \frac{a+c}{b+d}[/tex]

At this point:
[tex]\frac{0.5 km}{v_1}+\frac{3.5 km}{2v_1}=0.25 hr[/tex]

Multiply both sides by [tex]v_1[/tex] and remember how to add fractions!

[tex]\frac{a}{b}+\frac{c}{d}= \frac{ad+bc}{bd}[/tex]
 
Thanks again for your help! I'm new to the forum and still learning to navigate the site. I am taking an online physics course and will be needing your help in the future I'm sure. I'll be in touch.
 
Sure thing man. :) But I suggest you work a bit on your algebra first, since you'll be using it a lot!
 

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