The formula is an excercise for the reader, even if my audience was a 14 year old learning about this for the first time. As is figuring out why "mass" and "density" are unimportant.
Might be a valuable lesson in "reading the question carefully" for them, though, as the scenario was: "That’s pretty close when your neighbor just exploded", which is why orbital mechanics can be disregarded in this instance.
Might be a valuable lesson in "reading the question carefully" for them, though, as the scenario was: "That’s pretty close when your neighbor just exploded", which is why orbital mechanics can be disregarded in this instance.