1. **State the problem:** A bird is flying to the right (positive direction) and experiences a leftward acceleration of $0.5\ \text{m/s}^2$ for $3\ \text{s}$. After the gust stops, its velocity is $2.5\ \text{m/s}$ to the right. We need to find the initial velocity before the gust. 2. **Formula used:** The velocity after acceleration is given by the equation: $$v = v_0 + at$$ where: - $v$ is the final velocity, - $v_0$ is the initial velocity, - $a$ is the acceleration, - $t$ is the time. 3. **Assign values:** - $v = 2.5\ \text{m/s}$ (rightward, positive) - $a = -0.5\ \text{m/s}^2$ (leftward acceleration is negative) - $t = 3\ \text{s}$ 4. **Calculate initial velocity:** $$v_0 = v - at$$ $$v_0 = 2.5 - (-0.5)(3)$$ $$v_0 = 2.5 + 1.5$$ $$v_0 = 4.0\ \text{m/s}$$ 5. **Interpretation:** The bird's initial velocity before the gust was $4.0\ \text{m/s}$ to the right. **Final answer:** $$\boxed{4.0\ \text{m/s}}$$