An object with a mass of 12kg is lying still on a surface and is compressing a horizontal spring by 13m. If the spring's constant is 4kgs2, what is the minimum value of the surface's coefficient of static friction?

1 Answer
Apr 23, 2016

Force F required to compress a spring by x unit is
F=kx,where k = force constant.
Here x=13m
k=4kgs2
hence Force exerted on the object of mass 1 kg is F=4kgs2×13m=43kgms2=43N
This force is balanced by the then static frictional force as it is self adjusting one,

So the minimum value of the coefficient of static frictions
μs=FN,where N is the normal reaction exerted on the body by the floor. Here N=mg=129.8N
So
μs=FN=439.8×12=0.011