# An object with a mass of 7 kg is on a ramp at an incline of pi/12 . If the object is being pushed up the ramp with a force of  2 N, what is the minimum coefficient of static friction needed for the object to remain put?

Dec 28, 2015

The minimum coefficient of static friction is $0.237$

#### Explanation:

You have to visualize the force's diagram of the object.
Assuming the sistem with $x$ on the surface of ramp and $y$ on the normal of surface.
There is the orizontal component that is F(x)=|2N-(mgsin15°)|=15.7N
If the object remains "put": Friction Force=F(x)
F(f)=CF(y)=C(mgcos15°)=15.7N
and $C = \frac{15.7}{66.33} = 0.237$.