Engineering Statics

E-20


The coefficients of friction between the block and the incline are .035 and .025 for the static and kinetic cases. Determine whether the block is in equilibrium and find the magnitude and direction of the friction force.

The FBD of the block is drawn and x' and y' axes are specified 
downward along the incline and perpendicular to it.
Equilibrium can exist only if the frictional force between the box 
and plane can resist the other forces.
The force equation in the y' direction is written.
The normal force is found.
The force equation in the x' direction is written.