A lift starts from rest and rises with a steady acceleration of 1.2 m/s² for a short while…

Step 1. Velocity. $v = 1.2\ \text{m/s}^2 \times 2.5\ \text{s} = 3.0\ \text{m/s}$.

Step 2. Height. $s = \tfrac12 \times 1.2\ \text{m/s}^2 \times (2.5\ \text{s})^2 = 3.75\ \text{m}$.

Step 3. Rising 10 m. $t = \sqrt{\dfrac{2 \times 10\ \text{m}}{1.2\ \text{m/s}^2}} = 4.08\ \text{s}$.