A 0.43 kg particle moves in an xy plane according to x(t) = - 13 + 4 t - 3 t3 and y(t) = 26 + 9 t - 7 t2, with x and y in meters and t in seconds. At t = 0.7 s, what are
(a) the magnitude and
(b) the angle (within (-180°, 180°] interval relative to the positive direction of the x axis) of the net force on the particle, and
(c) what is the angle of the particle's direction of travel?