1. The problem statement, all variables and given/known data Yesterday, our physics class had a laboratory examination, in which we used a protractor as a "weight". We hung some paperclips and checked the angle. Then, they asked about the physical meaning of the slope of the graph: tan( angle) as a function of n( number of paperclips). The relation is linear. The slope has no dimensions, as you can see. 2. Relevant equations 3. The attempt at a solution Unsatisfied with the teacher's answer, which had mathematical meaning, I persisted to find the physical meaning. A slope can not be just a random value, it must be consisted of some constants. So, my intuition is that the slope is the ratio between the mass of a single paperclip and the mass of the counter side of the protractor. This is due to the fact that the bigger the mass of the paperclip is, the greater tan( angle) would be, so the mass must appear in the slope. I tried to prove it, or to find a general relation between the tan and n, but with no success. I would like to hear your ideas of what the slope could be. Thanks.