please solve

5. (6p.) A child's toy consists of three cars that are pulled in tandem on small frictionless rollers. The cars have masses mi= 3.1kg, m2 = 2.4kg and m3 = 1.2 kg. If they are pulled to the right with a horizontal force P = 6.5N, find a) the acceleration of the system, b) the force exerted by the second car on the third car, and c) the force exerted by the first car on the second car. m3