A 2.5 kg block is initially at rest on a horizontal surface. A horizontal force of magnitude F = 6.0 N and a vertical force of magnitude P are then applied to the block. The coefficients of friction for the block and surface are μ_s = 0.40 and μ_k = 0.25. Determine the magnitude of the frictional force acting on the block if ...(adsbygoogle = window.adsbygoogle || []).push({});

a) ...the magnitude of P is 8.0 N. (Hint -- is the block moving?)

b) ...the magnitude of P is 10 N. (Hint -- is the block moving?)

c) ...the magnitude of P is 12 N. (Hint -- is the block moving?)

Fn=-mg

Ff=μFn

I have been stumped with this problem for a long time now. I understand the force being applied is both horizontally and vertically and that I have to decompose each component but I have no clue on how to do it. I tried finding the normal force by multiplying the weight 2.5 kg by 9.8 m/s2 and then using the kinetic mu to find the force of friction but this was wrong. Please help! I am really stumped.

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# HELP! problem involving force of friction and normal force

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