A body of mass 7.5kg is to be pulled up along a plane which is inclined at 30degree to the horizontal. If the efficiency of the plane is 75%,what is the minimum force required to pull the body up the plane?

Answer 1

gravitational force parallel to the plane is...m * g * sin(30º)

If the efficiency of the plane is 75%, then the coefficient of friction is .25

the normal force is...m * g * cos(30º)

so the minimum force is
[m * g * sin(30º)] +
[m * g * cos(30º) * .25]