A mass of 200kg is resting on a rough inclined plane of angle 30^(@). If the coefficient of friction is1//sqrt(3) , find the greatest and the least force acting parallel to the plane which can just maintain the mass in equilibrium.

A mass of 200kg is resting on a rough inclined plane of angle 30^(@).

1.	A mass of 200kg is resting on a rough inclined plane of angle 30^(@). If the coefficient of friction is1//sqrt(3) , find the greatest and the least force acting parallel to the plane which can just maintain the mass in equilibrium.
Answer» SOLUTION :`F=mg(sintheta+mu_(k)COSTHETA)=200xx9.8[sin30+(1//sqrt(3))cos.30^(@)]=1960`, when the block TRIES to move up. When it SLIDES down, `mg sin theta=mgmu_(k)costheta`. So `F-0N`.