a. An artificial satellite travels in a very low circular orbit just above Earth’s surface with speed 7.9kms−1. Jupiter has mass 318 times Earth’s mass and radius 11.2 times Earth’s radius. Calculate the speed of an identical low circular orbit just above Jupiter’s cloud tops (answer to two significant figures).
b. Using your result from (i), find the ratio of this orbital speed to Jupiter’s escape speed at the same radius.