Question

What is the kinetic energy of a 200 kg satellite as it follows a circular orbit of radius 8x106m around the earth?

Answer 1

Given the equation for the Speed of a Satellite

v = SqRt{Gravitational Constant}{Mass of Earth} divided by the radius given in your problem

we have:


(square root whole term on right side)

v = G Me
———
r


so. (6.67x10^-11)(5.97x10^24)
___________________
(8.0x10^6)


v = 7055 m/s (which is reasonable)


so utilize the Kinetic Energy Formula


KE = 1/2mv^2


KE = 1/2(200)(7055)^2


KE = 4.977x10^9 J