What is the work done by the force field on a particle moving along a helix?

[withthemotive]

Homework Statement

Find the work done by the force field F(x, y, z) = 3xi +3yj + 7k on a particle that moves along the helix r(t) = 4 cos(t)i + 4 sin(t)j + 4tk, 0 ≤ t ≤ 2π (As in the previous problem, recall that the work of the force F on the helix corresponds to the circulation of this vector field along the curve).

Homework Equations

The Attempt at a Solution

F(x, y, z) = 3xi +3yj + 7k
r(t) = 4 cos(t)i + 4 sin(t)j + 4tk , 0 ≤ t ≤ 2π
r'(t) = -4sin(t)i + 4cos(t)j + 4

\intF(dot)dr
\int(-48cos(t)sin(t) + 48cos(t)sin(t) + 28)dt
\int (28)dt

With the integral going from 0 to 2pi I thought the answer would be 48pi, but it's not.

 

[withthemotive]

Nevermind, I got it, it's 28*2pi