2006-07-09 18:51:31 · 14 answers · asked by kp.eric 2 in Science & Mathematics ➔ Physics
No. However, it does change the direction of its motion vector.
2006-07-09 18:54:55 · answer #1 · answered by crao_craz 6 · 6⤊ 4⤋
The force of gravity of earth always pulls any object toward its center.
Therefore, the speed of the object will increase only when it is pulled in the direction towards the center of earth.
In the case of the satellite, it is moving in an orbit around the earth with certain speed.
If the speed of the satellite is zero, then it will be pulled toward the center of the earth.
But in general, if a force is applied in a perpendicular direction to the direction of motion of a body and if the force is always pointed toward a fixed point, then the body will move in a circular path with the fixed point as the center.
The radius of the circular path will depend upon the speed of the object. If the speed is small the radius is small and if the speed is higher the radius is big.
In the case of the satellite around earth, it is moving with certain speed parallel to earth surface at a place. The gravity acts perpendicular to the motion. Also the gravity is toward the center of the earth. Therefore, the satellite is moving in a circular path around earth; and the radius of the orbit depends upon the speed of the satellite.
If the speed of the satellite is reduced, for some reason, then it will move in an orbit of smaller radius.
Therefore, the answer to your question is, “As long as the satellite is having a constant speed, the gravity keeps it in a particular orbit. If the speed of the satellite is changed, the orbit is changed by the gravity.”
2006-07-09 21:17:28 · answer #2 · answered by Pearlsawme 7 · 0⤊ 0⤋
Gravity is constantly changing the velocity of the satellite. In a circular orbit, the speed will stay the same, but the direction will change continuously. That's because circular orbits are right at that point where the acceleration from gravity is equal to the acceleration needed to stay in a circle with fixed speed (which is why they're called circular orbits).
2006-07-09 18:57:40 · answer #3 · answered by gunghoiguana 2 · 0⤊ 0⤋
The value of speed remains constant.
The direction of the speed changes permanently. It is always directed as the tangent of the orbit at the position of the satellite.
By the way: there is no balance of forces, because there is only one force: the gravity.
To keep a body in a circular orbit with constant speed, you need a force pointed to the the center of of the circle orbit. This need is called centripetal force.
In this special case the centripetal force is delivered by the gravity.
2006-07-09 19:10:21 · answer #4 · answered by Thermo 6 · 0⤊ 0⤋
No. If the orbit is truly circular, the speed will be constant (except for losses caused by air resistance). In an elliptical orbit, which is what you have in almost all cases, the satellite speeds up as it approaches the planet, and slows down after passing the point of closest approach. Upon passing the point of farthest approach, it starts to speed up again.
2006-07-09 21:03:18 · answer #5 · answered by Anonymous · 0⤊ 0⤋
The phrasing of this question is very nice...like a GRE question.
no, if it's a *circular* orbit then the *speed* is constant. The velocity is changing at a constant rate though. The speed would change if this were anything other than a circular orbit.
You have to keep in mind that speed and velocity are different.
2006-07-09 21:11:21 · answer #6 · answered by idiuss 2 · 0⤊ 0⤋
***********************************************************************
I would think that this could happen if the orbit crossed several latitudes. The poles might have a greater force on a satellite. And since an orbit is held, the force of gravity would determine the speed at which a satellite must travel to maintain that orbit else it would break that orbit and change it's velocity and trajectory. If it broke orbit outward, it would leave the force of gravity and accelerate due to the reduction of pull. If it broke orbit inward, it would succumb to the force of gravity and accelerate exponentially. The greater it's angle in, the greater it's speed, in this instance.
This is just my guess though.
********************************************************************
2006-07-09 19:17:48 · answer #7 · answered by Alive and Well 3 · 0⤊ 0⤋
A fine point but not mentioned above.
Actually the orbits are not really 'circular', they are elliptical.
Some are just more less elliptical than others. A circular orbit is an earth impact waiting to happen'
Yours: Grumpy
2006-07-09 19:58:06 · answer #8 · answered by Grumpy 6 · 0⤊ 0⤋
Qithout the force of gravity the satelllite would not have a circular orbit. It is a
the balance between centrifugal force and gravity that causes the circular orbit
2006-07-09 18:56:41 · answer #9 · answered by Anonymous · 0⤊ 0⤋
Only if the altitude of the satellite changes. At a given altitude the force of gravity would be constant, therefore not affecting the velocity of the satellite.
2006-07-09 18:55:49 · answer #10 · answered by druid 7 · 0⤊ 0⤋
it is what keeps the satellite in a circular orbit. otherwise, it would go straight out into the universe.
2006-07-09 18:54:51 · answer #11 · answered by whatotherway 7 · 0⤊ 0⤋