Book moving and friction problem

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    Book Friction
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Homework Help Overview

The discussion revolves around a physics problem involving a book on a table, focusing on the forces required to initiate movement and maintain uniform velocity, considering static and kinetic friction coefficients.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the difference between the forces required to start moving the book versus those needed to keep it moving at a constant speed, referencing static and kinetic friction.

Discussion Status

Some participants have provided insights into the relationship between static and kinetic friction, indicating that different forces are required for initiating movement and maintaining motion. There is acknowledgment of varying interpretations of the problem, but no explicit consensus has been reached.

Contextual Notes

Participants discuss the coefficients of friction provided in the problem and the implications of these values on the forces required. There is a mention of specific numerical answers, but the focus remains on the conceptual understanding of the forces involved.

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Homework Statement




A BOOK LIES ON A TABLE WHICH HAS WIEGHT OF 8 NEWTON THE COEFICIENT OF STATIC FRICTION BETWEEN THE SURFACES IS 0.4 AND COEFICIENT OF KINETIC FRICTION IS 0.3 (1)HOW MUCH FORCE IS REQIURED TO MOVE THE BOOK(2)HOW MUCH FORCE IS REQUIRED TO MAKE IT MAVE WITH UNIFORM VELOCITY

Homework Equations




ACCTUALLY I HAVE SOLVED THE QUESTION I JUST WANT TO KNOW THAT IS MOVING THE BOOK AND MAKING THE BOOK MOVE WITH UNIFORM VELOCITY REQUIRE SAME FORCES?

The Attempt at a Solution

 
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FizixFreak said:
ACCTUALLY I HAVE SOLVED THE QUESTION I JUST WANT TO KNOW THAT IS MOVING THE BOOK AND MAKING THE BOOK MOVE WITH UNIFORM VELOCITY REQUIRE SAME FORCES?

(please don't shout :redface:)

No, the forces are different.

What solutions did you get? :confused:
 


The force require to "make it move" (initially) is proportional on the static friction. The force necessary to then make it move with uniform velocity is proportional to the kinetic friction. You do the same calculation but in the one case, use static friction and in the other kinetic friction.

Typically, as here, the coefficient of static friction is larger than the coefficient of kinetic friction so it takes less form to keep an object moving, once you have it started, than it does to make start moving in the first place.
 


HallsofIvy said:
The force require to "make it move" (initially) is proportional on the static friction. The force necessary to then make it move with uniform velocity is proportional to the kinetic friction. You do the same calculation but in the one case, use static friction and in the other kinetic friction.

Typically, as here, the coefficient of static friction is larger than the coefficient of kinetic friction so it takes less form to keep an object moving, once you have it started, than it does to make start moving in the first place.

thank you very much now i realized what a silly question i just asked thankx man
 


tiny-tim said:
(please don't shout :redface:)

No, the forces are different.

What solutions did you get? :confused:


the answer to (1)is 3.2 and the answer to (2)is 2.4/SIZE]
 
FizixFreak said:
the answer to (1)is 3.2 and the answer to (2)is 2.4/SIZE]


That's right!

3.2 N is needed to get it moving, but once it's moving, the force can be reduced to 2.4N for steady speed. :smile:
 

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