An object with a mass of 1kg is lying still on a surface and is compressing a horizontal spring by 1m. If the spring's constant is 7kgs2, what is the minimum value of the surface's coefficient of static friction?

1 Answer
Mar 6, 2016

Force F required to compress a spring by x unit is
F=kx,where k = force constant.
Here x =1m
k=7kgs^-2
hence Force exerted on the object of mass 1 kg is F=7kgs21m=7kgms2=7N
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=19.8N=9.8N
So
μs=FN=79.8=0.71