What actually happens in a space shuttle performing a circular motion?

Is it accelerating anyways...I guess it accelerates radially but not linearly or tangentially (I hope they both mean the same).



And what happens to the gravity? How does it disappear ??



Will the affect of gravity be still zero when its performing circular motion at a distance just above the surface of the earth (like at a height of 100m)

(I know its impossible but lets just say so AFTER ALL ITS PHYSICS!! ;) and thanks for answering!! )What actually happens in a space shuttle performing a circular motion?If by 'circular motion' you mean being in orbit, then the gravity is still there, but is balanced by the centrifuge force (the centrifuge force is an illusory one, but from the point of view of the shuttle, it is what is perceived). Seen from the actual official physics point of view, an object in orbit is simply free falling, but with the forward motion it has, it keeps missing the ground. When free falling, the gravity seems to vanish, but that is simply because it is not balanced by anything. If it makes it better for you to intuitively understand, one could claim that we do not feel gravity, ever. What we feel is the reaction that the ground exerts on our feet which balanced the weight. Remove the ground, and the feeling of weight goes away. Of course, to do that, you have to fall.

The altitude has nothing to do with it, the shuttle could be in orbit at 100 m altitude if it was not for the atmosphere dragging it down.



Edit: falan-filan answer below could be misleading. The Shuttle is nowhere near an altitude where the acceleration due to gravity is substantially reduced. The Earth radius is approximately 6370 km. The ISS (and thus the Shuttle when it goes there) orbits about 350 km about.
(6370 / (6370+350) )^2 = 0.9479

So, the acceleration due to gravity is almost 95% of the one we experience at sea level at the altitude the space station orbits. Rockets use their trust only to gain the altitude required to get out of the atmospheres, so that they can gain the orbital speed (tangential) without the drag of the air.
When leaving orbit, rockets do not use thrust to fight against gravity, they use it to accelerate further just going to a higher orbit, until the speed exceed escape velocity. That is why interplanetary probes trajectory are not straight lines, but always very elongated orbits.What actually happens in a space shuttle performing a circular motion?
No. 1. Gravity drag %26gt; Resistance drag until you reach a certain altitude. The higher you get the less is gravity drag. (Esc. velocity) http://en.wikipedia.org/wiki/G鈥?/a>

2. Once you reach escape velocity, there is yet another you need to reach to leave an orbit(esc. vel 2)

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What actually happens in a space shuttle performing a circular motion?3. He asked multiple questions and while d2 = d1 + 100 m is not a great difference wrt earth's radius, any dummy d for positions in the outer space could as well be. we send shuttles to Mars. actually, in space no air drag, therefore entering from one g field to another is the whole case.

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4. the comparability of different gravitational pulls on you completely have to do with your distance to each, and their masses. The effect of G(substantial or not) on you depends where you are in outer space wrt the two masses. It drops exponentially by 2nd order. Period.

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What actually happens in a space shuttle performing a circular motion?5. while thrusting you are moving up so the major thing you have to overcome is your weight(gravitational pull) + air drag where gravity has the greater effect but it is when you get rid of the drag that you can assume a position to fly tangentially to the orbit. (no wings like a plane)

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What actually happens in a space shuttle performing a circular motion?
6. otherwise your rocket would have to fly at enormous speeds in order to fly parallel to the earth's surface at 2000m altitude, like a plane, and not fall. (little cross sectional area no aerodynamics, no air buoyancy increaser-buoyancy is not drag). such a rocket has nothing to do with the topic.

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7. compared to 5. so after the trust and escape from the atmosphere, with the drag eliminated in vacuum, g field is what prevails(no thrust) and it is very important that some celestial object attracts you more as you approach it and another pulls you with a decreasing force (all due to distance).

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What actually happens in a space shuttle performing a circular motion?
if it is moving at a constant speed in this circular orbit(if it is not orbiting around something but just rotating like a car on a circular track), then yes the only thing that changes is the direction of motion so there is only radial acceleration f = ma = mw^2r = (mv^2)/r where w is the angular velocity in radians and r is radius so the linear velocity v = wr and a = (v^2)/r

linear velocity is just a term used to tell v from w, in that, a rotating round object, for instance the Earth has equal w along its longitudes (sweeps a constant angle at a certain period of time along horizontal lines at equal latitude) but as one approaches from the center of the Earth to its surface the arc length swept by this angle increases so you have to travel a greater distance 100m above the Earth(imagine a spherical surface whose radius is increased by 100m) to sweep the same angle in comparison to the length you'd have to travel on the surface of the Earth.


the tangential acceleration is the component of the resultant acceleration that is perpendicular to the radial one. tangential acceleration implies a change in the amount(magnitude) of velocity, whereas radial acc. implies a change in the direction of velocity.

so a car speeding up on a circular track has constant radial acceleration in magnitude but its speed is increasing so tangential velocity is increasing too.


gravity does not disappear, it's just reduced to negligible amounts: G = g*M1*m2/r^2

where G is the gravitational force, M1 and M2 masses of 2 objects that exert this gravitational force on one another(same in amount opposite in direction, you pull the earth towards you just as much as your weight meaning, the Earth pulls you towards itself with a force as much as your weight but by convention, the effect of the Earth on you is called gravity as its mass is much larger therefore contributing a lot more to G, so gravitational acceleration is always downward, towards the center of the Earth), and r is the distance between them.

so G decreases by the square of the distance between these objects. so gravity does not disappear. in fact that's why rockets' propulsion force is important for a rocket to be able to overcome gravity until it travels a distance where G is substantially reduced.

when it approaches another celestial object, then it enters the gravitational field of that object and if its tangential velocity cannot overcome the v in f = (mv^2)/r it will either rotate in that orbit or fall back to the surface of the planetary object.
so when this v equals the one in the formula so that it's just enough to escape, it's called escape velocity.