4.A 1 000-kg car is pulling a 300-kg trailer. Together, the car and trailer move forward with an acceleration of 2.15 m/s2. Ignore any force of air drag on the car and all friction forces on the trailer. Determine:
(a) the net force on the car,
(b) the net force on the trailer,
(c) the force exerted by the trailer on the car, and
(d) the resultant force exerted by the car on the road.