To find the acceleration of the object, we can use the formula for acceleration:
\[ \text{acceleration} = \frac{v_{\text{final}} - v_{\text{initial}}}{\text{time}} \]
Given:
- \( v_{\text{final}} = 8.0 , \text{m/s} \)
- \( v_{\text{initial}} = 0 , \text{m/s} \) (since the object is originally at rest)
- \( \text{time} = 2.0 , \text{s} \)
Now, substituting these values into the formula:
\[ \text{acceleration} = \frac{8.0 , \text{m/s} - 0 , \text{m/s}}{2.0 , \text{s}} = \frac{8.0 , \text{m/s}}{2.0 , \text{s}} = 4.0 , \text{m/s}^2 \]
Thus, the acceleration of the object is
\[ \boxed{4.0 , \text{m/s}^2} \]
The correct answer is b: 4.0 m/s².