Voyagers 1 and 2 surveyed the surface of Jupiters moon Io and photographed active volcanoes spewing liquid

Question:

Voyagers 1 and 2 surveyed the surface of Jupiter’s moon Io and photographed active volcanoes spewing liquid sulfur to heights of 70 km above the surface of this moon. Find the speed with which the liquid sulfur left the volcano. Io’s mass is 8.9 X 1022 kg, and its radius is 1 820 km.