You slide a box of books at constant speed up a 30^\circ ramp, applying a force of 210N directed up the slope. The coefficient of sliding friction is 0.18. 1. How much work have you done when the box has risen 2m vertically? 2.What is the mass of the box? I think I could solve this if I was given the mass of the books The pushing force is given, but how do you find the force of the friction with no mass to find the normal force. Once I get the force of friction I would just add it to the pushing force (210) and multiply by distance to get the work done.