28. Commercial airplanes are sometimes pushed out of the
passenger loading area by a tractor. (a) An 1800-kg tractor
exerts a force of 1.75x10* N backward on the pavement,
and the system experiences forces resisting motion that total
2400 N. If the acceleration is 0.150 m/s2, what is the mass
of the airplane? (b) Calculate the force exerted by the tractor
on the airplane, assuming 2200 N of the friction is
experienced by the airplane. (C) Draw two sketches showing
the systems of interest used to solve each part, including the
free-body diagrams for each.