Question

Several volcanoes have been observed erupting on the surface of one of Jupiter's closest moons. Suppose that material ejected from one of these volcanoes reaches a height of 4.96 km after being projected straight upward with an initial speed of 132 m/s. Given that the radius of this particular moon is 1990 km, calculate its mass.


I have tried solving for g with g=(GM)/(r^2), and taking my calculated g and solving for mass using the equation M= (g*r^2)/(G) but my homework site tells me that the answer is wrong. I keep getting the answer 1.04x10^20 kg.

Answer 1

g =G•M/R^2,
h =v^2/2•g = (v•R)^2/2•h•G =
=(132•1990•10^3)^2/2•4.96•10^3•6.67•10^-11
= 1.04•10^23 kg

Answer 2

thanks!!!