I dont know why but Im having a little problem with this problem here: Two spacecraft are 13,500 m apart and moving directly toward each other. The first spacecraft has velocity 525 m/s and accelerates at a constant −15.5 m/s2. They want to dock, which means they have to arrive at the same position at the same time with zero velocity. (a) What should the initial velocity of the second spacecraft be? (b) What should be its constant acceleration? Here is my work: used vf = vi + at to get 33.87 s for time for the 1st aircraft used displacement = 1/2(vi + vf)t to get 8891 m then 13500m - 8891m = 4609 m for distance traveled for the 2nd aircraft used displacement = 1/2(vi + vf)t to get 272 m for the vi of the 2nd aircraft (answer to a) then used vf = vi + at to get -8.04 m/s^2 for acceleration of the 2nd aircraft (answer to b) if you plug these numbers in and add up both equations then they equal to 13500 m but somehow Im wrong? Am I using the wrong formulas or have made an err in my math? can somebody please help?