An object with a mass of #10 kg# is on a plane with an incline of # - pi/4 #. If it takes #12 N# to start pushing the object down the plane and #7 N# to keep pushing it, what are the coefficients of static and kinetic friction?

1 Answer
Mar 9, 2018

Answer:

#mu_s = 0.173#
#mu_k= 0.101#

Explanation:

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#pi/4# is #180/4 deg = 45 degrees#

The mass of 10Kg on the incliine resolves to a 98N force vertically.
The component along the plane will be :

#98N * sin45 = 98 * .707 = 69.29N#

Let the static friction be #mu_s#

Static Friction force =#mu_s* 98 * cos 45 = 12#

#mu_s = 12/(98*0.707) = 0.173#

Let kinetic friction be #mu_k#

Kinetic Friction force =#mu_k* 98 * cos 45 = 7#

#mu_k= 7/(98*0.707) = 0.101#