Answer
$v_{com} = [(2.35~t)~\hat{i}-(1.57~t)~\hat{j}]~m/s$
Work Step by Step
In part (a), we found that the acceleration of the center of mass in unit-vector notation is:
$a_{com} = (2.35~m/s^2)~\hat{i}-(1.57~m/s^2)~\hat{j}$
We can find the velocity of the center of mass:
$v_{com} = v_0+a_{com}~t$
$v_{com} = 0+a_{com}~t$
$v_{com} = [(2.35~t)~\hat{i}-(1.57~t)~\hat{j}]~m/s$
