Problem 11. Find the mass of a wire bent in the shape of the curve r(t) (3t, 32,2t where 0 t1, if the density at r(t) is 1 t gram per unit length. Line integrals of a vector field Problern 12. Find the work of the force field F = (z, y,z+y-1) along the segment of a straight line connecting the points 1) and (2,3,4). Problem 13. Caleulate the integral where C is the curve r(t) = (t12, t19 tao17) between the points t = 0 and t = 1.