Friction/Dynamic Equilibrium Help

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Homework Help Overview

The problem involves a pickup truck carrying a steel file cabinet and requires determining the shortest stopping distance to prevent the cabinet from sliding. The context is centered around friction and dynamic equilibrium.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the need for the coefficient of friction and question whether additional information, such as masses, is provided. There is an exploration of using known values from reference materials. The original poster expresses uncertainty about how to start the problem, while others suggest focusing on the forces acting on the cabinet and the role of static friction.

Discussion Status

The discussion includes various interpretations of the problem, with some participants providing insights into the forces involved and suggesting a method to calculate the stopping distance. However, there is no explicit consensus on the approach, and the original poster indicates a solution has been reached.

Contextual Notes

The coefficient of friction is not provided in the problem statement, leading to reliance on external resources for values. The participants are navigating the implications of this missing information in their reasoning.

acpyrus
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A pickup truck with a steel bed is carrying a steel file cabinet. If the truck's speed is 15 m/s, what is the shortest distance in which it can stop without the file cabinet sliding?

*---*--*-*
v(i)=15m/s
v(f)=0
Need to find x(f)

Friction: f(s) should be F(net) = 0?

Not sure where to start.
 
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Are you given a coefficient of friction for the cabinet?
Are you given any other information, such as masses?

I just reread the question:

I think you need to find the coefficient yourself, for steel on steel.
 
Last edited by a moderator:
Coeffiecient of friction is not given on the problem, however I did find a steel-on-steel f(s) in a table in our text --> where f(s) = 0.80
 
I am pretty sure the question should be solved as such:

The only force on the cabinet is the static friction.
Due to the cabinet's inertia (since it is already moving forward), the net force is not equal to zero. We want the friction force to move the cabinet in the opposite direction of motion so that it will not slide.

Net force on the cabinet:
Fnet = Fs

ma = μmg
a = μg

Use a kinematics equation to solve for distance, using the calculated acceleration and the known change in velocity.
 
Last edited by a moderator:
I came up with 14.3m - which is correct. Thanks.
 

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