potential. (d) Can you try to guess/explain a rule for the existence of a potential o, based on Exercise 4 - Escape velocity using vector line integrals. Consider a spaceship that is traveling from the surface of the Earth to space in a straight line. We are going to compute the work necessary to perform to make the spaceship can exit the gravitational field of Earth. The (normalised) gravitational force is given by: (x, y, z). F(x, y, z) = 1 (x + y+z2)3/2 Let us parametrise the trajectory of the spaceship in the following way: r(t) = t(1, 1, 1) for 1 < t