Given the graph below with the initial velocity, v1=-6m/s, the object starts with one value of constant acceleration and stops at 3.6 seconds. then the value of its acceleration changes to a different acceleration. Finally at t1=6.7 seconds it travels at a constant final velocity. After t2=12.8 seconds, the average velocity of the entire trip is 2.5 m/s in the positive X direction. Determine the final velocity in m/s