1. The problem statement, all variables and given/known data The angular velocity vector of a rigid object rotating about the z-axis is given by ω = ω z-hat. At any point in the rotating object, the linear velocity vector is given by v = ω X r, where r is the position vector to that point. a.) Assuming that ω is constant, evaluate v and ∇ X v in cylindrical coordinates. b.) Evaluate v in spherical coordinates. c.) Evaluate the curl of v in spherical coordinates and show that the resulting expression is equivalent to that given for ∇ X v in part a. 2. Relevant equations The expressions for the curl in cylindrical and spherical coordinates. Since I don't know how to put the determinant here ill just leave them out. For spherical x = r sinθ cosΦ y = r sinθ sinΦ z = r cos θ 3. The attempt at a solution So I worked out part a correctly (I think) which is in the attachment, but I'm stuck on part b. b.) So for this part I have to convert ω to spherical coordinates. Since ω only lies along the z-axis, that means that Φ and θ are equal to zero, so ω = ω r-hat and the position vector in spherical polars is R = r r-hat so that means that when I cross ω and R I get zero, I don't know what I'm missing.