Answer:5.6
Step-by-step explanation:2.8×12=12×9.8-8/3v^2
33.6=117.6-8/3v^2
8/3v^2=117.6-33.6
8/3v^2=84
8v^2=84×3
8v^2=252
V^2=31.5
V=√31.5
V=5.6125
V~5.6