How Should the Second Crewman Pull to Align the Boat's Net Force Forward?

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Homework Help Overview

The problem involves two crewmen pulling a boat through a lock, with one crewman pulling at an angle of 32 degrees and the other at 45 degrees. The goal is to determine the force with which the second crewman should pull so that the net force on the boat is directed forward.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the required force for the second crewman but arrives at an incorrect answer. Some participants suggest breaking the forces into components and redefining the coordinate system to clarify the problem.

Discussion Status

Participants are exploring different approaches to the problem, including the suggestion to redraw force vectors and consider their components. There is no explicit consensus on the correct method or solution at this time.

Contextual Notes

The original poster expresses uncertainty about their calculations and the feedback from a computer program indicating an incorrect answer. There is mention of potential issues with significant figures.

jcais
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Hello,

I was wondering if someone could help me with a homework problem for non-calculus based physics:

Two crewmen pull a boat through a lock. One crewman pulls with a force of F1 = 150 N at an angle of 32 degrees relative to the forward direction of the boat. THe second crewman, on the opposite side of the lock, pulls at an angle of 45 degrees. With what Force F2 should the second crewman pull so that the net force of the two crewmen is in the forward direction?

F1 is F subone and F2 is F subtwo

THank you for your help!:confused:
jcais@msn.com

I worked the problem out by this but have the wrong answer:

F = -F1Sintheta1/Sintheta
= -(150N)sin32 degrees/sin(-45degrees) = 116N

the computer program is saying this is wrong.

I tried 120N to maybe b/c sig figs. Not sure

Thanks!
 
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HINT: If the boat is traveling in the y direction then what is the x component of the force exerted by the first crewman.
 
Hello

I am not sure. That might be the solution to my problem, but I just can't figure it out. Can you help me? Thank you for your time and input.

:redface:
 
redefine your coordinate system so that the forward direction of the boat is the x-axis. Then redraw your force vectors, break them into components and try to solve again.

Draw a picture it really helps.
 
if the answer is 179.9N approximately 180N and u need a detailed solution email me at demooreonline@yahoo.com with the subject physics: question.
bye
 

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