Question #fa936

1 Answer
May 9, 2016

The only magnitude which changes is the linear momentum. Angular momentum and kinetic energy are constant.

Explanation:

The satellite which is revolving in a circular orbit around the Earth has gravity force, pulling towards the Earth, in balance with the centrifuge force, pulling towards the space,

Fg=FcGMmr2=mv2rv2=GMr

where

M = mass of Earth ; m= mass of satellite ; r= distance from the satellite to the centre of Earth ; G= gravitation constant

Therefore, the module of speed of satellite is constant, so the module of linear momentum is constant but not its direction. A satellite in circular orbit has as linear momentum

p=mv=mv(-icosθ+jsenθ) where θ is the angle of the satellite in relation with axis X.

The kinetic energy is defined as Ek=mv22, thus as the module of speed is constant, Ek is contant.

As the orbit of the satellite is flat the angular momentum is conserved, consequently, does not change.