hi,
just a bit6 confused about your notation on the original question. im not sure whether youve missed something out but it wounds wierd.
eg: "Total resistance acting on them is 550N" but then you say "Resistance acting on car is 800k and on trailer, is 300k." how can that be if the total is 550N?? also you say 800k is k a unit of something cos ive never heard of that! or is it 800k as in 800,000 ?
EDIT: ignore the above (just left in there so you can see my train of thought). you used k instead of K which got me confused!. so now im guessing K is a constant that you have to find? now i understand how you get K ( 550 = 800K + 300K ). but how did you find the driving force?
from your layout of the question it looks as though its two seperate parts. but in the first part you dont say whether the car is accelerating or still or what, so i dont know how you found the driving force. and the incline of the slope isnt mentioned until d) so i didnt think that applied for the first part.
could you just clear up a few things, or im gonna get paranoid because i think im missing something obvious!