What Forces Keep the Book Stable on an Inclined Bookshelf?

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AI Thread Summary
The discussion focuses on calculating the forces acting on a book resting against an inclined bookshelf. The total force exerted by the left side of the bookshelf is 2.17 Newtons at an angle of 59 degrees. To maintain stability, the force from the bottom of the bookshelf must counteract both the gravitational force and the horizontal component of the force from the side. The participant realizes the need to adjust their calculations to account for gravitational force, indicating confusion about the angle's reference point. Clarification is sought on whether the 59 degrees is measured from the vertical or horizontal.
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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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