Mechanics of space travel.?
365929
V = at, so 1.5x10^8 = 98*t => t = 3,061,224 seconds or 850 hours.  Something might be wrong here because things get weird as you near the speed of light, but it seems right.  You have to remember that 10G is very very difficult to keep up for long.  On a typical space ship, you may remember they have 3 helper rockets.  Those probably get around 10G, but they run out within a few minutes and they're very big already.  So, keeping it up for 850 hours would be kind of tough.\n\nAcceleration in space works by "throwing" things, such as the expanding gases of the burning fuel, out the back of the space shuttle.  With conservation of momentum, it propels the spaceship forward.  The problem is that you can only throw so much out the back before you run out.  And in space, there's almost nothing to "pick up" to throw out the back, except for the very rare space particles once in a while.\n\nWith no acceleration, a ship will move at constant velocity, so you do not need more and more to keep up the same speed.  There is a slight bit of drag in space from the particles so that would eventually slow the spaceship down after a very long time.  Some of the futuristic designs for spaceships actually involve thrust that's about as strong as the weight of a piece of paper.  So, the ship will very very slowly gain speed, but it can do so for an indefinite period of time.\n\nWe don't use nuclear power in space because it's too dangerous.  If one of them explodes like Challenger did, it would be a global nightmare.  So, no one does it.  There's also the fear that nuclear weapons might be used as an offensive weapon from space.\n\nEdit: Yes, you're right.  The ship needs more and more thrust as you approach c because the ship is getting heavier.  At very small speeds, you don't, but we're dealing with relativistic speeds.\n\nThe formula is kind of tough to write out.  There's a lot of special relativity on this page: http://www2.slac.stanford.edu/vvc/theory/relativity.html\n\nAt .5c, the time dilation is pretty small.  It's around a factor of 1.15.  See the link here: http://www.fourmilab.ch/cship/timedial.html\n\nI didn't bother to look up the thurst in Newtons and calculate it out, but I really doubt something with that little thrust can get to near the speed of light.  If you look at the link below, you can see rocket power is one of the worst ways for propulsion.\n\nAll of the sci-fi ships are the ones that might get closer with various technologies.\n-Exploding nuclear bombs out the back (very early on, people thought this might work\n-Nuclear would really help (fusion especially)\n-VASMIR\n-Antimatter drives\n\nThere are a ton here: http://en.wikipedia.org/wiki/Spacecraft_propulsion
1018278
that would depend on the velocity of the craft, the velocity the at you were pushed out with respect to the velocity of the craft, and what near by celestial or terrestrial bodies were near, to influence your movement with their gravitational pull...  if you wre set outside a ship, with zero velocity, and left, out in deep space... you would remain essentially motionless... if the same were done to you near the earth, you wold fall to the earth.. if you were pushed out the side door of the space shuttle while it orbited... you would most likely orbit several time before your orbit decayed and you would have a incredibly painful reentry... as short as the pain might be...
315403
You would generate a ship capable of providing a mini-ecosystem capable of sustaining a self-replicating crew.  Astronauts have kids who become astronauts down the ages until the destination is reached.  \n\nAs far as drive mechanism, currently NASA is working on finalizing an ION drive that gets stuff to its destination faster than our current thruster tech by propelling them at an increasing rate of acceleration.
1148300
All space garbage should be recycled and composted into an ecosystem. Thats the complicated set of chemistry questions that goes wtih that particular problem.\n\nUsing large enough diameters and centripetal force we can generate strong enough and stable enough pseudo\ngravity to compensate for that problem. A chemical problem with a civil engineering fix.
451224
In theory, a very light weight space craft with a very large area "sail" could use pressure from sunlight itself to accelerate. Note that it is the actual sunlight, as in photons, that exert the force, not the solar wind, which is a stream of particles from the Sun. The solar wind does not exert nearly as much force as the light does. Hard to believe, but true.
933949
Theory of relativity.
703424
This is a very basic question and you need to get extra help if you are having trouble solving this in your physics class.\n\nAcceleration is force / mass.  (from F = ma).\n\nThus, for the astronaut\n\n120 = 79(a)\na = ~1.52m^2/s\n\nAnd the satellite\n\na = 0.182\n\nNow they travel in opposite directions (BOTH of them move). So calculate how far the astronaut travels, how far the satellite travels, and add them. Simple kinematics:\n\np = 2a(t^2) + v(t)
470138
As everybody else noted, the theoretical space journey would take 300 years in earth terms or 298.5 years aboard ship.\n\nThis presents you for some challenges in your story-in-progress as you would need:\n\na) a long-lived character or characters like Robert Heinlein's Lazarus Long; or\n\nb) generations of people born and raised on board ship with new generations trained in running a spaceship; or\n\nc) the passengers kept in hibernation while the crew is manned by androids and advanced computers.
804445
First you want to know the acceleration due to gravity of the planet Glob. At the surface the gravitational acceleration (g) can be determined by equating the weight of an object with the gravitational force law\n\nm*g = G*M*m/R^2\n\nwhere R is the radius of Glob, M is Glob's mass, G is the universal gravitational constant, and m is the mass of the object. Solving for g yields\n\ng = G*M/R^2\n\nNow, throwing an object into the air, and neglecting air resistance, we can consider conservation of energy. The kinetic energy of the object when it is released by the astronaut is completely converted into potential energy when the object reaches the top of its travel.\n\n0.5*m*V^2 = m*g*H\n\nwhere V is the initial speed of the object and H is the height to which it traveled, and g is the gravitational acceleration solved for above. Solving for V we find\n\nV = sqrt(2*g*H).\n\nThe satellite traveling in a circular orbit of radius D above the planet has its centrifugal force balanced by the gravitational force of the planet.\n\nFc = m*v^2/D = G*M*m/D^2 = Fg\n\nSolving for the speed of the satellite (v) needed in order to maintain orbit at radius D yields\n\nv = sqrt(G*M/D).
989278
The effect which causes weight is actually an acceleration, and in the case of on the surface of Earth it is due to gravity.  Weight may also be caused by acceleration due to motion in a straight line, such as with astronauts during liftoff having their weight "increased".\n\nSo to answer your question depends upon if any acceleration or deceleration is happening during the journey.  If the astronauts are moving toward another planet at a constant speed, then they are completely weightless.  (Well, they will of course be pulled a very tiny amount toward any gravitational sources, but unless they are massive and nearby, the effect will be practically insignificant.)  If they are moving under acceleration, then they will feel "weight" based upon the amount of acceleration.
475251
If I remember correctly from my high-school physics class, it's a combination of gravity and one of Newton's laws of motion - the one that says "an object in motion stays in motion unless acted on by an outside force." So that force keeps it moving around and gravity keeps it from just flying off into space.
426626
I assume you are asking what do they use while spacewalking.  In space there is a lack of gravity, this means that the astronauts can't use the same screwdriver or ratchet we do.  Specially design tools have been made to assist them with their work.
334240
Well, completely aside from size, light-speed travel is currently impossible by our technology. When and if that technology is ever invented, I would say 'yes', because there is no such thing as wind resistance in space ^_^
117099
Space shuttle gains huge potential and kinetic energy as it goes up and orbits earth. This energy needs to be given out as it comes down. This happens in form of heat. Heat is generated in the process of slowing down the craft. \n\nIf we want to reduce the speed by means of spending energy, while it coes down we need to send up even larger amount of fuel to equilize gravity as it comes down. This will result in very bad design.\n\nMay be with nuclear powered plasma engines oe day we shall be able to bring the craft slowly. But that will not reduce the risk. The plasma wlll then be inside the vehicle, rather than outside of it. So we got to learn the art of handling super hot gases either way.
39004
Its not impractical because you have perpetual motion in space get it spinning and it will spin forever at the same speed.  No friction.  Thats the only way to do it because you can create Gravity like on startrek
381192
Rocket Principles\nA consquence of Newton's laws of motion is that for any object, or collection of objects, forces which only involve those objects and nothing else ("internal forces") cannot shift the center of gravity. For example, an astronaut floating in a space suit cannot shift his position without involving something else, e. g. pushing against his spacecraft. The center of gravity--or "center of mass"--is a fixed point, which cannot be moved without outside help (turning around it, however, is possible).\n\nBy throwing a heavy tool in one direction, the astronaut could get moving in the opposite direction, though the common center of gravity of the two would always stay the same. Given a bottle of compressed oxygen, the same result follows from squirting out a blast of gas (a scene that appeared in an early science fiction film). A rocket does much the same, except that the cold gas is replaced by the much faster jet of glowing gas produced by the burning of suitable fuel. At present, rockets are the only means capable of achieving the altitude and velocity necessary to put a payload into orbit.\n\nA rocket engine is a machine that develops thrust by the rapid expulsion of matter. Most rockets today operate with either solid or liquid propellants. The word propellant does not mean simply fuel, as you might think; it means both fuel and oxidizer. The fuel is the chemical rockets burn but, for burning to take place, an oxidizer (oxygen) must be present. Jet engines draw oxygen into their engines from the surrounding air. Rockets do not have the luxury that jet planes have; they must carry oxygen with them into space, where there is no air.\n\nThere are a number of terms used to describe the power generated by a rocket. \n\n\nThrust is the force generated, measured in pounds or kilograms. Thrust generated by the first stage must be greater than the weight of the complete launch vehicle while standing on the launch pad in order to get it moving. Once moving upward, thrust must continue to be generated to accelerate the launch vehicle against the force of the Earth's gravity. To place a satellite into orbit around the Earth, thrust must continue until the minimum altitude and orbital velocity have been attained or the launch vehicle will fall back to the Earth. Minimum altitude is rarely desirable, therefore thrust must continue to be generated to gain additional orbital altitude.\n\nThe impulse, sometimes called total impulse, is the product of thrust and the effective firing duration. A shoulder fired rocket has an average thrust of 600 lbs and a firing duration of 0.2 seconds for an impulse of 120 lb-sec. The Saturn V rocket, used during the Apollo program, not only generated much more thrust but also for a much longer time. It had an impulse of 1.15 billion lb-sec.\n\nThe efficiency of a rocket engine is measured by its specific impulse (Isp). Specific impulse is defined as the thrust divided by the mass of propellant consumed per second. The result is expressed in seconds. The specific impulse can be thought of as the number of seconds that one pound of propellant will produce one pound of thrust. If thrust is expressed in pounds, a specific impulse of 300 seconds is considered good. Higher values are better. A rocket's mass ratio is defined as the total mass at lift-off divided by the mass remaining after all the propellant has been consumed. A high mass ratio means that more propellant is pushing less launch vehicle and payload mass, resulting in higher velocity. A high mass ratio is necessary to achieve the high velocities needed to put a payload into orbit.\n\nThere are three categories of chemical propellants for rocket engines: liquid propellant, solid propellant, and hybrid propellant. The propellant for a chemical rocket engine usually consists of a fuel and an oxidizer. Sometimes a catalyst is added to enhance the chemical reaction between the fuel and the oxidizer. Each catego
1119730
ahh, good theory problem...\nlet's see, there's energy, friction, force (normal, tension, as well as the other ones mentioned), gravitation, mass, pendulum motion, gotta be more that I've missed, but no doubt someone'll be here to correct me.