更新1: If I throw a ball horizontally with a very high speed
and a *** all constant force is acted on the ball downwards
it should eventually fall to the ground. But why the satellite do not fall to the ground by its weight? What is the difference beeen o cases?
As I have pointed out in my reply to your question that the motion of an objects depends on o factors: (i) the initial condition (i.e. mostly initial velocity) of the object
and (ii) the force that acts on the object
and which subsequently gives an acceleration and velocity to the object. When the weight of the satellite acts on the satellite
because the direction of force and the initial velocity of the satellite are at right angle to each other
the force does not give any change of velocity in the direction of the "initial velocity". Instead
there is an acceleration and change of velocity in the direction which the force (i.e. the weight) acts. As a result
you could visualize that the resultant velocity of the satellite would be "deflected" from the direction of the "initial velocity" towards the direction which the force acts. However
once the path traversed by the satellite is "deflected"
the force that acted on the satelite also changes in direction
in such a way that it (the force) is always perpendicular to the velocity of the satellite. Thus
the process described in the preceding parapgraph repeats. The final scenario is that the satellite traverses a circular path around the earth. You could pare the situation of just throwing a stone horizontally on earth surface with that of a satellite. In the former case
the force (i.e. the weight) always acts in one direction
which is vertically downward irrespect to the direction of velocity of the stone on its path. Thus a parabolic path is resulted. In the satellite case
the force keep changing in direction along with the change of velocity direction
which results to a circular path.
Is it true that the satellite actually moves towards the earth but just it is unnoticeable? Answer: It is actually not the case. In fact
the satellite does not move to the Earth. Consider the case when satellite is not pulled towards the Earth by its weight
the satellite will not move in orbits. It will only move in a straight line unless other forces act on it. Hence
the weight is actually causing the orbit motion by antagonizing the straight movement of the satellite
rather than moving it towards the Earth. If I throw a ball horizontally with a very high speed
and a *** all constant force is acted on the ball downwards
it should eventually fall to the ground. But why the satellite do not fall to the ground by its weight? What is the difference beeen o cases? Answer: Refer to the previous wer
the satellite does fall. But it is actaully 'balanced' by the straight line motion of the satellite
causing it to move in orbits. And in fact
the cases of satellite and throwing ball is more or less the same. If the velocity of the thrown ball is high enough
the ball move travel in a certain horizontal distance before it falls vertically. In this case
the ball moves in orbits
like satellite.
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