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A satellite of the Earth has a mass of 104 kg and is at an altitude of 1.98 106 m. (Assume that U = 0 as r .)
(a) What is the potential energy of the satellite-Earth system?
(b) What is the magnitude of the gravitational force exerted by the Earth on the satellite?
(c) What force does the satellite exert on the Earth?

2007-11-19 05:06:08 · 2 answers · asked by thisguyneedshelp121 1 in Science & Mathematics Physics

2 answers

Kill Physics right back!

a) Pe=GMm/R
M- mass of the Earth
G- gravitational constant
m - mass of the object
R - distance between centers

b)F=GMm/R^2

c) Hmmm... I,m sure it is F=GMm/R^2 ;-)

2007-11-19 07:38:05 · answer #1 · answered by Edward 7 · 0 0

Gravitational potential energy is given as "mgh". "h" refer to the distance from earth core to the satellite, "g" the gravitational acceleration, "m" the mass of the satellite.

"mgh" can be derived from one of Newton's Law "F=ma" and the definition of work, "Work=Fd", where "F" is the applied force and "d" is the distance it moves. Things that had work applied to it has increase in kinetic energy (if it move horizontal) or potential (if it move vertically). In case of "mgh", "mg" refer to Gravitational Force, and "h" the vertical distance.

therefore
b) =mg
c) =mg. Why? Because both object pull each other at same strenght .Consider; Earth pull the satellite torward it, therefore the satellite move torward Earth. But; meanwhile in the satellite point of view the satellite appeared stationary, the Earth seem to be moving torward it, which appeared like; the satellite is pulling Earth.

a) =mg(h-r). "h-r".... because it is said that the potential energy is 0 at "r". "r" is the radius of Earth. "h-r" is the height of the satellite.

2007-11-19 07:16:58 · answer #2 · answered by Anonymous · 0 0

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