Answer:
50.176 [m].
Explanation:
1) the required height can be calculated using the formula:
h=V₀*t+1/2* g*t₂, where V₀ - initial velocity of the rock, t - elapsed time, g - 9.8 m/s²;
2) if V₀=0, t=3.2, g=9.8, then
h=0.5*9.8*3.2²=1024*49*10⁻³=50.176 [m].≈50[m].