- #1
justinh8
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Homework Statement
What is the change in gravitational potential energy of a 64.5-kg astronaut, lifted from
Earth’s surface into a circular orbit of altitude 4.40 3 102 km?
The Attempt at a Solution
Ok, i know to find this i have to find the gravitational energy on Earth using Earth's radius and find the gravitational energy in orbit using the Earth's radius + the altitude. Therefore, the equation at Earth would be Eg = -GMm/re and the equation in orbit would be
Eg = -0.5(GMm/re + altitude).
However, in the solutions manual it uses the same equation Eg = -GMm/re when the object is in orbit.
I just want to know if the book is wrong or if i am wrong. I thought that when objects are in orbit you have to play in the value of kinetic energy which creates the equation of Eg = -0.5(GMm/re + altitude). Please explain