physics

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A 5-kg box is pushed across a horizontal floor by a 20-N force that is angled 30 degrees
below the horizontal. What is the coefficient of kinetic friction between the box and the floor if
the box is pushed at a constant speed?

• physics -

ma=Fcosα-F(fr)
ma=0
F(fr) = μmg
Fcosα= μmg
μ=Fcosα/mg =
=20•cos30/5•9.8=0.35

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