Question 1181762
Here's how to calculate the average acceleration and velocity:

**A. Average Acceleration**

1. **Convert units:**
   * Initial speed (vᵢ) = 30 km/h * (1000 m/km) * (1 h/3600 s) = 8.33 m/s
   * Final speed (v_f) = 0 m/s (since it comes to a stop)
   * Time (t) = 20 minutes * (60 s/minute) = 1200 s

2. **Calculate average acceleration:**
   Average acceleration (a) = (v_f - vᵢ) / t = (0 m/s - 8.33 m/s) / 1200 s ≈ -0.00694 m/s²

3. **Magnitude of acceleration:**
   The magnitude is the absolute value of the acceleration.  |a| ≈ 0.00694 m/s²

**B. Average Velocity**

1. **Calculate average velocity:**
   Average velocity (v_avg) = (vᵢ + v_f) / 2 = (8.33 m/s + 0 m/s) / 2 ≈ 4.17 m/s

**Answers:**

*   **A. Magnitude of average acceleration:** Approximately 0.00694 m/s²
*   **B. Magnitude of average velocity:** Approximately 4.17 m/s