- #1
crosbykins
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Homework Statement
How much work is done against gravity to fire a 7.2*10^2 kg weather monitor 120km into the air.
Homework Equations
Mass Earth = 5.98*10^24kg
radius of Earth = 6.38 * 10^6 m
Eg = -GMm/r
delta Eg = Eg 2 - Eg 1
The Attempt at a Solution
Eg1= -[(6.67*10^ -11N * m2 /kg2 )(5.98*1024 kg)(7.2*102 kg)] /(6.38*106 m)
= -4.50 *1010 J
Eg2= -[(6.67*10^ -11N * m2 /kg2 )(5.98*1024 kg)(7.2*102 kg)] /(6.38*106 m + 120 *103 m)
= -4.49 *1010 J
delta Eg = -4.49 *1010 J - -4.50 *1010 J
= 1.0*108 J
***my solution is based off the idea delta Eg is equal to work done...is this correct?