1. The problem statement, all variables and given/known data List 2 major factors result in an efficiency of less than 100% when using an inclined plane to raise a mass Note - this is a grade 11 lab so don't have answers that are too advanced please :D 2. Relevant equations eff = eout/ein x 100% .... = mghf/fd x 100% 3. The attempt at a solution I listed friction as one with the explanation: friction (thermal energy) when the block with mass was being pulled up the inclined plane, it experiences a force of kinetic friction opposite to the applied force. This is a result of the chemical bonding between surfaces. Since W = Fd, an increase in applied force was needed at first to overcome static friction, then kinetic friction after. An increase in applied force will result in an increase of work as they are proportional and the displacement did not change. Since friction can never be fully eliminated and is usually not the useful energy, there will be efficiency that is less than 100%. I have no clue what the 2nd major factor is though. It was not sound as it was a small block and didn't make noise going up the ramp. Should I just use sound as my second factor?