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## Homework Statement

Place a book flat on a table and press down on it with your hand. Now suppose the hand-book and table- book values of are 0.50 and 0.40, respectively; the book's mass is 0.90 kg and your downward push on it is 10 N. How much horizontal force is needed to keep the book moving at a constant speed if your hand is stationary with respect to the table?

## Homework Equations

F=ma

## The Attempt at a Solution

The given values for friction kinda threw me off but this is my attempt to it

Fa= 10 N (force applied)

Fg=mg = .90•9.8 = 8.82 N

Fn = mg+ Fa = 18.82 N

Ff = Uk•Fn = .40•18.82 = 7.528

Since it’s going at a Constant speed , it means there’s no acceleration and all the forces are equal to Each other .

So the horizontal force needed wouldn’t it be the same as the Friction force (Ff) .

The correct answer should be 12.5 N

Where did I go wrong ?

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