An object with a mass of 5kg is on a surface with a kinetic friction coefficient of 4. How much force is necessary to accelerate the object horizontally at 9ms2?

1 Answer
Mar 29, 2016

Fx=5(9.410)25N

Explanation:

enter image source here

Draw a free body diagram, FBD:
x-axis:
Fx=ma;FxFμk=ma Newton Law ===>(1)
Summation of all Forces ma

y-axis:
Fy=ma;FwN=0;Fw=mg=N Newton Law
Fμk=μkN=μkmg ===>(2)

Insert (2) into (1):

Fxμkmg=ma Solve for Fx
Fx=maμkmg=m(aμkg)

Now m=5kg;μk=.4;a=9ms2
Fx=5(9.410)25N

A word of caution, a kinetic friction, μk=4 is very large, I suspect you meant to say .4 which reasonable. I assumed .4. If you want μk=4 just correct for it.