Originally Posted by

**adamcobz** Is this the right way to work out these answers?

1 - Car has weight of 1500kg and is travelling along a straight, horizontal road

a) i) Car has negligible(?) resistance to its forward motion and is accelerating at 0.5 m/s2. Calculate the driving force

Using F=ma, F=1500x0.5 = 750N

ii) The car has a driving force of 2500N and total resistance to its forward motion of 250N. Calculate acceleration

Again, F=ma, 2500-250=1500a, 1500a=2250, a=1.5m/s2

b) Car of mass 1500kg is pulling 900kg trailer along straight horizontal road. The connection is light, rigid and horizontal. Driving force of 600N acting on car

i) give the horizontal forces acting on the car and trailer seperately

Car=> forward=600N, backwards=tension(T1) and friction (muR)=(mu1500g) would you include friction?

Trailer=> forward=600N(?) and tension(T2), backwards=friction (muR)=(mu900g)

ii) calculate the acceleration of the car and trailer. Also calculate the force in the coupling stating whether it is a tension of a thrust

Im not too sure how to do this part, I know it would require F=ma but when I do it, it leaves too many unknowns

iii) In a new situation, the trailer has a resistance to motion of 300N and the car has a resistance RN. There is no driving force and there is zero tension in the coupling calculate R