Determine the acceleration of the body.

To determine the power delivered to the body, we need to find the resultant force and the velocity at the given time, then calculate their dot product.

Step 1: Determine the acceleration of the body.
The velocity vector is given by $\vec{v} = (2t\hat{i} + 4t\hat{j})$ m/s.
Acceleration is the derivative of velocity with respect to time:

$$\vec{a} = \frac{d\vec{v}}{dt} = \frac{d}{dt}(2t\hat{i} + 4t\hat{j})$$ $$$$