A flowerpot falls from rest off a balcony 12 m above the pavement…

Step 1. Time. $t = \sqrt{\dfrac{2 \times 12\ \text{m}}{9.8\ \text{m/s}^2}} = 1.56\ \text{s}$.

Step 2. Speed. $v = \sqrt{2 \times 9.8\ \text{m/s}^2 \times 12\ \text{m}} = 15.3\ \text{m/s}$.

Step 3. The first 10.2 m. $t = \sqrt{\dfrac{2 \times 10.2\ \text{m}}{9.8\ \text{m/s}^2}} = 1.44\ \text{s}$.

Step 4. The last 1.8 m. $1.56\ \text{s} - 1.44\ \text{s} = 0.12\ \text{s}$.