Figure 8-16: http://www.webassign.net/walker/08-16.gif(adsbygoogle = window.adsbygoogle || []).push({});

12. [Walker2 8.P.002.] Calculate the work done by friction as a 2.1 kg box is slid along a floor from point A to point B in Figure 8-16 along paths 1, 2, and 3. Assume that the coefficient of kinetic friction between the box and the floor is 0.21.

Since work can have a negative number, I'm assuming that all 3 answers will be the same, since the displacement is 3 meters. Path 1 travels 4 - 1 = 3 meters, Path 1 travels 2 + 1 = 3 meters, and Path 3 travels 3 meters. The vertical travels will not be affected by friction.

W = f * d

d = 3

f = friction

friction = mu * N (force Normal)

N = ma

N = 2.1 * 9.81

N = 20.601

friction = 0.21 * 20.601 = 4.32621

W = 4.32621 * 3

W = 12.98 j

but this is wrong, and so is -12.98.

Thanks in advance for your input

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# Homework Help: Work friction problem

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