Problem: You want to nail a 1.1 kg board onto the wall of a barn. To position the board before nailing, you push it against the wall with a horizontal force F to keep it from sliding to the ground. If the coefficient of static friction between the board and the wall is 0.71, what is the least force you can apply and still hold the board in place?(adsbygoogle = window.adsbygoogle || []).push({});

Thoughts: fsmax= coeffcient of friction*N.

I'm having trouble finding N because I'm used to it being parallel to W and in this case it's perpendicular. Without knowing the F the han dis exerting on the board I'm not sure how to go about finding N.

What I have tried is simply doing N as mass*gravity to get 10.79 then multiplying by the .71 but the online homework system is saying that answer is wrong.

Obviously there's something I'm not understanding correctly. Any help would be appreciated.

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# Homework Help: Trying to find a normal force

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