The figure below shows an object of unknown mass m, held by a massless string on a frictionless inclined surface. The angle θ is also uknown. If a tension of magnitude T = 5.8 N and a normal force of magnitude N = 9.7 N act on the object, what is the mass m? http://img161.imageshack.us/img161/4345/q3qs7.gif [Broken] I can't seem to find an equation in my textbook that I could manipulate in order to find the unknown mass, using the givens. Any help would be much appreciated, thanks.