To find the rate of acceleration, you can use the formula for acceleration:
\[ a = \frac{{v_f - v_i}}{{t}} \]
Where:
- \( v_f \) is the final velocity
- \( v_i \) is the initial velocity
- \( t \) is the time
In this case:
- \( v_f = 5 , \text{m/s} \)
- \( v_i = 30 , \text{m/s} \)
- \( t = 2.5 , \text{s} \)
Now, substitute the values into the formula:
\[ a = \frac{{5 , \text{m/s} - 30 , \text{m/s}}}{{2.5 , \text{s}}} \]
\[ a = \frac{{-25 , \text{m/s}}}{{2.5 , \text{s}}} \]
\[ a = -10 , \text{m/s}^2 \]
The acceleration of the boat is \( -10 , \text{m/s}^2 \). The negative sign indicates that the boat is decelerating.