1. The problem statement, all variables and given/known data 1. You stand on a spring-loaded bathroom scale in a bathroom. The scale "reads" your mass. What is the scale actually measuring? 2. Similarly, you stand on a spring-loaded bathroom scale in an elevator that is accelerating upward at 2.0 m/s^2. The scale "reads" your mass. What is the scale measuring? A) Your mass B) Your weight C) The force of the scale pushing up on your feet D) The force of your feet pushing down on the scale 1. A large rock falls on your toe. Which concept is most important in determining how much it hurts? 2. Similarly, if the large rock merely sits on your toe, which concept is most important in determining how much it hurts? A) The mass of the rock B) The weight of the rock C) Both the mass and the weight are important. D) Either the mass or the weight, as they are related by a single multiplicative constant, g. 2. Relevant equations Weight = mg = dp/dt Impulse = Δp = mΔv 3. The attempt at a solution For 1,2: To me, C seems correct for both of them, but B also seems correct for the first part, as weight is equal to the force of the scale on your feet for that part. For 3,4: For a falling rock, to me it seems that mass would be most important as the pain level would be proportional to the change in momentum, or the impulse, on your foot. For a stagnant rock, it seems either weight or mass would be the same.