Finding coeffiecient of friction

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Homework Help Overview

The discussion revolves around determining the coefficient of friction between a book and the floor after it slides to a stop. The problem involves concepts from kinematics and energy conservation.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss various methods to find the coefficient of friction, including using kinematic equations and conservation of energy. Questions arise regarding the accuracy of the original poster's calculations and the need for clarification on the equations used.

Discussion Status

There is ongoing exploration of different approaches to the problem, with some participants providing feedback on the original poster's attempts. Guidance has been offered regarding the need to verify equations and consider approximations in calculations.

Contextual Notes

Participants note potential issues with approximations in calculations and the relevance of certain variables, such as mass and gravitational acceleration, in the context of the problem.

ross moldvoer
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Homework Statement


You give a 2.85kg book an initial shove at 2.98m/s and it comes to rest after sliding 3.80m across the floor.
Find the coefficient of friction between book and floor.

Homework Equations


vf^2=vo^2+ad
f=ma

The Attempt at a Solution


0=2.98+a*3.8
=2.33
 
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I think you'll need to explain your attempt. What were you trying to accomplish?
 
i tried solving for a in order to use f=ma
 
First, verify that your relevant equation is written correctly and not missing any constants.

Next, I don't see where in your attempt you accounted for squaring the initial speed. You don't seem to have applied the relevant equation.
 
ross moldvoer said:

Homework Statement


You give a 2.85kg book an initial shove at 2.98m/s and it comes to rest after sliding 3.80m across the floor.
Find the coefficient of friction between book and floor.

Homework Equations


vf^2=vo^2+ad
f=ma

The Attempt at a Solution


0=2.98+a*3.8
=2.33
 
I did with conservation of energy. By equating kinetic energy to the frictional work done,

1/2*mv^2=(mu)*N*d

Where m is mass
v is initial velocity
mu is coefficient of friction
N is normal force i.e. mg
d is distance travelled

I got an answer, mu = 0.16
 
jatin9953 said:
I did with conservation of energy. By equating kinetic energy to the frictional work done,

1/2*mv^2=(mu)*N*d

Where m is mass
v is initial velocity
mu is coefficient of friction
N is normal force i.e. mg
d is distance travelled

I got an answer, mu = 0.16
Going another route, I arrived at the same expression. But - I seem to have a slightly different answer: μ≈0.12.
 
That could be possible because of certain approximations in the calculation, like value of "g", or something else, i guess.
 
jatin9953 said:
That could be possible because of certain approximations in the calculation, like value of "g", or something else, i guess.
No, 0.16 looks too inaccurate for that. Note that the mass is irrelevant.
But more seriously, you are not supposed to present something so much more Like a complete solution than the original poster has yet managed. Gneill's post is the right sort of hint.
 

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