3. A particle experiences a force field that may be written in spherical coordinates as F = -40e +1e. Under the influence of this force field, this particle moves from the north pole to the equator on a sphere of radius 2. Its coordinates, as a function of time, are: r(t) = 2, 6(t)=t, q(t) = /2,0/2. Compute the work done, W = [F-dr, by the force field in moving the particle by using spherical coordinates and unit vectors.