Aspacecraft on its way to mars has small rocket engines mounted on its hull; one on its left surface and one on its back surface. at a certain time, both engines turn on. the one on the left gives the spacecraft an acceleration component in the x direction of ax = 5.10 m/s2, while the one on the back gives an acceleration component in the y direction of ay = 7.30 m/s2. the engines turn off after firing for 645 s, at which point the spacecraft has velocity components of vx = 3780 m/s and vy = 4470 m/s. what was the magnitude and the direction of the spacecraft's initial velocity before the engines were turned on? express the magnitude as m/s and the direction as an angle measured counterclockwise from the +x axis.