The helicopter view in the figure below shows two people pulling on a stubborn mule. (Take F. = 138 N and F, = 61.0 N.) F1 75.00 60.00 (a) Find the single force that is equivalent to the two forces shown. magnitude N direction counterclockwise from the +x-axis (b) Find the force a third person would have to exert on the mule to make the net force equal to zero. magnitude N direction counterclockwise from the +x-axis