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## Homework Statement

This thing was a part of an entire question . I solved the other parts but I don't know why I am messing up here .

Force required to keep a wooden block from sliding on a rough incline with coefficient of friction μ

## Homework Equations

Force on a block on an inclined plane ,

towards the ground : m*g*sin(θ)

due to friction in opposite direction of the above force is m*g*cos(θ)

where m is the mass of the block , g is the gravitational acceleration and θ is the angle the incline makes with the horizontal.

## The Attempt at a Solution

So I pictured something like this

Initially

http://awwapp.com/s/38/18/09.png [Broken]

Now if I apply a force to stop the block from sliding the FBD should be something like this

http://awwapp.com/s/5a/44/08.png [Broken]

So the force I have to apply ( the blue one ) should be Force due to gravity - Force due to friction

F = mg(sin(θ) -μcos(θ))

But the answer given is

F = μ*m*g*cos(θ)

How is this possible

Sorry about the drawings

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