What Forces Keep the Book Stable on an Inclined Bookshelf?

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Homework Help Overview

The problem involves a book resting at an angle on an inclined bookshelf, with a focus on the forces acting on the book to maintain its stability. The subject area includes concepts from mechanics, specifically forces and equilibrium conditions.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the equilibrium of forces acting on the book, including gravitational force and the forces from the bookshelf. There is an attempt to set up equations based on the sum of forces in both x and y directions. Questions arise regarding the interpretation of the angle provided in the problem.

Discussion Status

The discussion is ongoing, with participants exploring different approaches to set up the equations correctly. Some guidance has been offered regarding the relationship between the forces and the gravitational force, but there is no explicit consensus on the correct interpretation of the angles involved.

Contextual Notes

Participants are considering the implications of the angle measurement (whether it is from vertical or horizontal) and how that affects their calculations. There is also a mention of the gravitational force acting on the book, which is a critical factor in the analysis.

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Homework Statement


A 0.407 kg book rests at an angle against one side of a bookshelf. The magnitude and direction of the total force exerted on the book by the left side of the bookshelf are given by:

Force Left = 2.17 Newtons and θ=59 degrees

What must the magnitude and direction of the total force exerted on the book by the bottom of the bookshelf be in order for the book to remain in this position?

Force book = ___?___Newtons
θ = ___?___degrees


Homework Equations





The Attempt at a Solution



Sum of forces in x:

2.17sin(59) - Fcos(θ) = 0 => Fcos(θ) = 1.86

Sum of forces in y

2.17cos(59) + Fsin(θ) = 0 => Fsin(θ) = -1.1176

tan(θ) = (-1.1176)/(1.86) => θ = 211 degrees

F = 2.17 N

this is wrong though
 
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The sum of the forces in y must counter the force exerted by gravity, which is m g.
 
So I was in the right track?
I just need to change my formula to 2.17cos(59) + Fsin(θ) = mg
 
Is the 59 θ the angle from vertical or the angle from horizontal?
 

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