1. The problem statement, all variables and given/known data A sphere of radius 1.06 cm is dropped into a glass cylinder filled with a viscous liquid. The mass of the sphere is 13.0 g and the density of the liquid is 1146 kg/m3. The sphere reaches a terminal speed of 0.166 m/s. What is the viscosity of the liquid? Variables (in standard units): Radius of sphere: 0.0106 m Mass of sphere: 13.0 g Density of liquid: 1.146*106 g/m3 Terminal speed: 0.166 m/s Variables I calculated: Volume of sphere 4/3*pi*0.0106 m=0.0444 Density of sphere 13.0/0.0444=292.793 2. Relevant equations (densityobject-densityfluid)Vg=6*pi*viscosity*r*v 3. The attempt at a solution (292.793-1.146*106)(0.0444)(9.8)/6*pi*0.0106*0.166 This gives me a value of -1.50*107 Pa * s. Obviously I don't think viscosity can be negative and that negative value is coming from my computation of drag (densityobject-densityfluid. So I'm thinking something is wrong there. Thanks for the help.