1. ## wire density

Consider a wire in the shape of a helix with constant density function

a) find the mass
b) determine the coordinates of the center of mass
c) determine the moment of inertia about the z-axis

The one example I have seems to be quite different and I cant follow it anyway. Any help setting up this problem, I would appreciate.

2. im still working on this
i thought the answer may have been along these lines

find r'(t). and then find the dot product with the density.
then work out the integral from 0 to 2pi
the integral changes back into the original r(t) equation, and by subbing in 2pi and then subtracting the substitution of 0 I ended up with 10pi, which is not the answer for the mass