[SOLVED] mastering physics answers wrong just wanted to know if anyone else is using the program mastering physics for homework and getting wrong answers to the questions. This has happened to me a few times and im sure their answers are completely wrong. For example a simple work problem with a force pushing a block up a ramp. when asked for the work in joules of friction force you find first the normal force multiply that by the coefficient of friction then substitute in the formula W=F times displacement times cos theta correct? And normal force is perpendicular to the plane of the incline. For example the explaination of their answer normal force of a 1 kg box being pushed up an incline was equal to 9.8N? which is not right if normal force is perpendicular the plane of the incline. am i crazy or is this program giving wrong answers?