Conservation of Momentum and Energy in Fisherman-Boat Interaction

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Homework Help Overview

The discussion revolves around a problem in the context of conservation of momentum and energy, specifically involving a fisherman jumping into a rowboat. The scenario includes calculations related to the initial and final velocities of both the fisherman and the boat.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of momentum conservation principles, with one attempting to calculate the final velocity using initial momentum and total mass. Questions arise regarding the correctness of calculations and the interpretation of directionality in the problem.

Discussion Status

The discussion is active, with participants verifying calculations and questioning the implications of directionality in their results. Some guidance has been offered regarding the sign of the final velocity, indicating a productive exploration of the problem's assumptions.

Contextual Notes

Participants are working under the constraint that east is defined as the positive direction, which influences their calculations and interpretations of velocity signs.

Ronaldo21
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Basic Momentum and Energy!

Note: Take East as the positive direction. A(n) 88 kg fisherman jumps from a dock
into a 123 kg rowboat at rest on theWest side of the dock.
If the velocity of the fisherman is 4.1 m/s to the West as he leaves the dock, what is the
final velocity of the fisherman and the boat?
Answer in units of m/s.

so do i just do 88 times 4.1 and get 36.08
then do (88+123)v and get 211v
then do 36.08=211v and solve for v??
 
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Yes, because initial momentum = 88*4.1 and final momentum=(88+123)v.
 


no because i did that and got 360.8 = 211V
then i solved for v and got 1.709952607 and it said i got it wrong.
did i do anything wrong?
 


Look at what direction is positive. You solved correctly

The answer would be -1.71m/s
 


-? why negative??
 


Right, trick question! "Note: Take East as the positive direction."
 


ohh! gotcha!
thank you very much!
 

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