Step 1: Identify known parameters
Initial velocity, \( u = 20 \, m/s \)
Final velocity at peak altitude, \( v = 0 \, m/s \)
Gravitational acceleration, \( g = 9.8 \, m/s^2 \) (acting downwards)
Step 2: Select appropriate kinematic formula
\[ v^2 = u^2 - 2gh \] Here, \( h \) represents the maximum altitude.
Step 3: Insert values and compute \( h \)
\[ 0 = (20)^2 - 2 \times 9.8 \times h \implies 400 = 19.6h \implies h = \frac{400}{19.6} \approx 20.41 \, m \]
Step 4: State the conclusive result
Approximated to the nearest option: \( h = 20 \, m \).