Final answer:
The average acceleration during the 3rd second is -8 m/s^2.
Step-by-step explanation:
To find the average acceleration during the 3rd second, we need to find the acceleration function first. We can do this by taking the derivative of the velocity function. In this case, the velocity function is given as v(t) = 4t-2t^2. Taking the derivative of this function, we get the acceleration function a(t) = 4 - 4t.
Now, to find the average acceleration during the 3rd second, we substitute t = 3 into the acceleration function. a(3) = 4 - 4(3) = 4 - 12 = -8 m/s^2.
Therefore, the average acceleration during the 3rd second is -8 m/s^2.