Posted by Sarah on Saturday, June 11, 2011 at 10:30pm.
A 990 kg car is pulling a 300 kg trailer. Together, the car and trailer have an acceleration of 2.13 m/s2 in the forward direction. Neglecting frictional forces on the trailer, determine the following (including sign).
(a) the net force on the car
(b) the net force on the trailer
(c) the force exerted by the trailer on the car
(d) the resultant force exerted by the car on the road.
magnitude N
direction ° measured from the left of vertically downwards

physics  bobpursley, Sunday, June 12, 2011 at 5:31am
F=ma on the car, m=990+300
on the trailer, m=300 
physics  Kenneth, Sunday, April 17, 2016 at 6:12pm
considering we use Newtons second law, we also have to logically conclude that we are individually find each object's net force. Therefore we neglect the other mass i.e. we plug in Newtons second law for the car Fnet = (990)(2.15), considering we are isolating the objects we ignore the second mass: hence the answer for part A is
~= 2128.5. Now part B will be the same thing using the same logic we did for part A. In part D you tak into account both masses therefore in your answer you add the masses. Fnet = 1290*2.15... Lol Idk how to solve c but A,B and D that is how you solve it.