I'm sitting a Mechanics paper as one of my Maths modules tomorrow and I'm stuck on a practice question, please can someone help if they can.

A car is towing a trailer along a horizontal straight road using a horizontal tow-bar. The masses of the car and the trailer are 1050kg and 200kg respectively. The resistance to motion of the car is 850N and the resistance to motion of the trailer is 150N.

Question

At an instant when the driving force exerted by the car is 1100Nm find,

a) the acceleration of the car

b) the pulling force exerted on the trailer

At another instant the pulling force exerted on the trailer is zero

a) show that the acceleration of the car is -0.75m/s/s

b) find the driving force exerted by the car

a) F = ma

1100 = (1050 + 200)a

1100/1250 = a = 0.88m/s/s

Do I need to use the resistances in the above?

b) What is the pulling force? Is it like a resistive force?

Um, and I don't understand the rest

Please can someone explain it to me.

Many thanks,

Delta