How long would it take a cannon ball to orbit the earth given that the radius of the(adsbygoogle = window.adsbygoogle || []).push({});

earth is 4000 miles and the height of the (quite fictitious) mountain is 800 miles?

Me = mass of earth

Mc = mass of cannon ball

R = earth's radius

v = 2piR/T

4000 mi = 6437200 meters

a = acceleration of cannon ball

G = 6.67e-11

Using an applet for a previous question, I found Vo to be 15468 miles/hr. But I didn't use Vo... Instead I used Fnet = GMeMc/r^2 as follows.

Fnet = GMeMc/r^2 = Mca = (Mc(2piR/T)^2)/R -->

GMe/r^2 = (4pi^2*R^2)/RT^2 -->

r^2/GMe = T^2/(4pi^2*R) -->

sqrt(4pi^2*R^3)/GMe = T

my result was 5138s, which is about 85.6 minutes.

Does my work and result look all right?? thanks in advance

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# Homework Help: LEO cannon ball

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