1. The problem statement, all variables and given/known data A pickup truck has a mass of 2400 kg when empty. It is driven onto a scale, and sand is poured in at the rate of 150 kg/s from a height of 3.0 m above the truck bed. At the instant when 440 kg of sand have already been added, what weight does the scale report? 2. Relevant equations $$ J=\Delta p=mv_1-mv_0 $$ $$ w=mg $$ 3. The attempt at a solution I can't quite see what this has to do with impulse, and whether or not kinematics have to be used in this at all or not.