a) A block weighing 9.1N requires a force of 2.8N to push it along at constant velocity. What is the coefficient of friction for the surface?(adsbygoogle = window.adsbygoogle || []).push({});

b) A weight "W" is now place on the the block and 8N is needed to push them both at constant velocity. What is weight "W" on the block?

This is what I got:

Since it is constant velocity, there is no acceleration, therefore Fnet is 0, therefore Ff is 2.8N.

Normal force is (9.1)(9.8) =89.18N

Formula: Ff=uN

2.8=u(89.18)

2.8/89.18=u

Therefore u= 0.031

, but that's not the right answer... Why? what did I do wrong?

I take it I need to know a before I can do b?

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# Homework Help: Coefficient of friction for surface

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