what is the escape speed on a spherical asteroid whose radius is $496$km and whose gravitational acceleration at the surface is $0\mathrm{.}970$m$/$s$^2.$ b$)$ how far from the surface will a particle fo if it leaves the astroid's surface with a radical speed of $663$m$/$s$?$ c$)$ with what speed will an object hit the astroid if it is dropped from $869\mathrm{.}0$ km above the surface