Hello, I'm conducting an experiment about how contact force and surface quality affect friction. I know that friction is affected by both, as my data suggests. I measured the static forces of several weights on two different surfaces, and found that indeed the max static force increased as the weights got heavier. For analysis, I'd like to calculate the coefficients of the max static forces, and I know this is equal to (max static force / normal force), but I'm wondering how to calculate the normal forces of each weight. Is it just equal to the mass of each weight times gravity?? Thanks so much!