Solving Force Problem: Finding Velocity and Force Requirements

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Homework Help Overview

The problem involves determining the force required to accelerate a system of bodies to a velocity of 30 ft/s after moving 20 ft from rest. The context includes considerations of work, kinetic energy, and friction.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between work done and kinetic energy, questioning the relevant equations and the role of kinetic friction in the problem.

Discussion Status

The discussion is active, with participants exploring the implications of kinetic friction on the forces involved. Some guidance has been provided regarding the relationship between work and kinetic energy, but no consensus has been reached on the specific equations to use.

Contextual Notes

There is a mention of a kinetic friction coefficient of 0.20, which raises questions about its impact on the calculations. The original poster has not provided all necessary details regarding the system setup.

the_d
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My problem is to find the force needed to give the system of bodies a velocity of 30 ft/s after moving 20 ft. from rest.

Can anyone help me with this? All i have done is found EFx and EFy for the 50lb weight
 

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Didn't you post this question earlier? (Or was it someone else with the same question?) As said, use the fact that the work done by that force on the distance of 20 ft equals the change of kinetic energy.
 
is there an equation for that??
 
the_d said:
is there an equation for that??

If you know the definition of work, and the definition of kinetic energy, you should be able to write down this equation yourself.
 
so W = KE, where does the coeffeficient of kinetic friction play in all this??
 
the_d said:
so W = KE, where does the coeffeficient of kinetic friction play in all this??

You didn't mention any kinetic friction coefficient.
 
sorry, the kinetic friction is 0.20...
 
does that play a role??
 
the_d said:
does that play a role??

Yes, it does, because you have to include the force of friction into your sum of forces acting on the object.
 
  • #10
ok, i got ya
 

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