Posted by jacky on .
At t = 0, a particle moving in the xy plane with constant acceleration has a velocity of vi = (3.00 i  2.00 j) m/s and is at the origin. At t = 2.00 s, the particle's velocity is v = (6.60 i + 4.00 j) m/s.
Find the acceleration of the particle at any time t. (Use t, i, and j as necessary.)

PHYSICSS!!!!! 
drwls,
Subtract the two vector velocities from one another and divide the difference by 2.00 s to get the vector acceleration.
Since acceleration is said to be constant, it will be valid at all t.