✨ Best Answer ✨
0.98=1/2×0.50×0²+0.50×9.8×h+1/2×49×(0.20-h)²
0.98=0.50×9.8×h+1/2×49×(0.04-0.40h+h²)
0.98=4.9h+(0.98-9.8h+1/2×49×h²)
1/2×49×h²-4.9h=0
1/2×10×h²-h=0
5h²-h=0
h²-0.20h=0
h(h-0.20)=0
h=0.20[m]