Suresh pushes a create with a mass of 50KG down a slope with a rough surface, using a pushing force of 45N parallel to the slope downward. The slope is 2m in length. The inclination of the slope is 40 degrees. The crate starts at rest at the top of the plane. the frictional force between the plane and the crate is 140N. calculate the net force exerted on the crate.