Moving particle acceleration problem

[Melchior25]

Homework Statement

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 = 2.50 s, the particle's velocity is v = (6.10 i + 4.90 j) m/s.

(a) Find the acceleration of the particle at any time t. (Use t, i, and j as necessary.)

Homework Equations

avg. acceleration = change in Velocity / Change in time

The Attempt at a Solution

I subtracted the two vectors (vf -vi) and this is what I got for my equation to find acceleration of the particle at any time t.

avg accel. = (3.10i+6.90j)/t

but when I entered this into the web page I got the answer wrong. Any suggestion would be appreciated.

 

[Leong]

constant acceleration means a fixed number. so it will not be in term of t. simply divide by 2.5 s to get the number.

right?