Force required to level out a bookshelf with weights on it

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To keep the bookshelf level while holding a 5.0 kg stack of books, Leif and Paige must exert forces that balance both the weight of the books and the shelf's weight. The system is in static equilibrium, meaning the net force and net torque must equal zero. A free body diagram can help visualize the forces acting on the shelf. Leif needs to exert a force of 50 N upwards, while Paige must exert 10 N upwards. Understanding these forces is crucial for maintaining balance in this scenario.
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Homework Statement



Leif and Paige are rearranging the heights of their movable bookshelves; they remove one of the 2kg, 0.6 m long shelves by the two of them holding opposite ends. A 5.0 kg stack of books is piled up on the shelf 0.2 m from Leif. How much force must Leif and Paige each exert to hold the shelf level?

Homework Equations



F = ma

The Attempt at a Solution



F = 1 * 5 * 10
F = 50 N up from Leif

F = 10 N up from Paige

I don't know how to calculate the mass in

Help please, i need like step by step help please, i don't think very good thanks
 
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the system you describe is in static equilibrium.

conditions for static equilibrium are:
net force = 0
net torque = 0

there are four forces acting here, it will help to draw a free body diagram for this problem.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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