If velocity is relative, what is it relative to?
336972
Wow, great question(s)!  You're brooding over something called the 'twin's paradox', read more about it in the link below.  Basically, what you're fretting over are a couple of the (wierd) implications of special (and general) relativity.  You (and what some others have said) are right, all velocity is relative, which comes from the simple fact that there is no special place that we can call 'still' which we could measure our velocity against.  The single exception to this lies in the speed of light, which is constant for everyone everywhere, no matter what their speed is relative to anything else.  (Note: light isn't special, the only reason it's able to travel at the upper speed limit is because it's particles, photons, have no mass.  Nothing with mass can ever travel AT the speed of light, only near if it is pumped up with huge amounts of energy.)  Think about the wierd implications of this; even if you were able to travel at 99.999999% the speed of light, and your friend would also be able to travel the same speed in the opposite direction, if you shined a light back toward your friend and could measure the photon's speed as they travelled between you the photons would STILL be travelling at the speed of light.  Ok, what does that mean?  The speed of light is just a speed, like any other, but is a constant that can not be exceeded.  Well, like any other speed, c (the usual symbol for the speed of light) is definded as the ratio of the distance travelled (call it 'x') by the time it took to travel it (call it 't'), or c=x/t.  But if 'c' can't change (because it's a constant) what is changing?  There's only two other things in the equation, x (the distance, a measure of space) and t.  Time and space enter into Einstien's equations here, the only way to keep c constant is for x and t to somehow collaborate to change together to make it so.  This is why time (and space) are so 'relavent' to velocity.  And as a matter of fact, time is 'relavent' to gravity as well, as Einstein pointed out so much better than I can.  For Einstein, the breakthrough came when he realized that there is no measurable way to distinguish between gravity and acceleration (a.k.a. the rate of change of velocity with respect to TIME), or more importantly, between the lack of gravity (say a person floating in space) and a particle (or person) in a falling box, they're indistinguishable.  From these two simple ideas (the constancy of c, and the equivalence of gravity and acceleration) Einstein formulated the theory of general relativity, one of the crowning achievements of human thought.  You ask good questions, keep wondering!
454697
Which graph du you use? velocity verses time or velocity versus distance?
337266
Um, well it depend on how you consider light. If you consider it as a stream of photons, then you might say that if you measure the positions of each of those photons it doesn't have velocity.\nIf you say it is a wave and always in motion then it is not relative to your velocity, exactly. Even if you were travelling at 30000000mph the light would still appear to be travelling at 3x10to the power of 8 m/s away from you. Light is the fixed speed limit for the universe. But at the far reaches where the material of space itself is expanding into nothing, it is expanding at a speed greater than the speed of light because that speed limit only applies to objects moving within the universe.
24383
here are some simple mechanics formulas dealing with velocity:\n\nv=d/t\na=v/t\nvf^2=vi^2+2ad\nd=vit + 1/2at^2\n\nwhere v is velocity, vi is initial velocity, vf is final velocity, a is acceleration, and t is time.  also the i and the f after the v are just subscripts, and ^2 just means sqared.
978564
Velocity is the speed an object is moving at and the direction that it is moving in. For example, if you said that a car was going 60 mph due east you would be talking about velocity; if you merely said that the car was moving 60 mph you would just be talking about its speed. You would measure acceleration by measuring an objects speed at two different times (the closer the more accurate your number estimate), subtract the difference and divide by the time interval. For example, if at time=1, the speed of an object was 5 meters per second, and at time=4 the speed was 14 meters per second you would do the following: (14-5)/(4-1)=9/3=3 meters/sec^2.\nRegarding  your last question, if the skateboard was going 5mph when you started your experiment, then your initial speed would b 5mph.
796826
Velocity is a vector quantity.\nSo,if two velocities happen to be parallel to each other(same or opposite direction ),they are added algebraically.i.e.mere sum or difference as the direction would be same as the two given vectors.\n\nab----------------->      cd<------\nThen resultant   ------------------------->\n  +                                                         \n.............................................<--------\n=........................--------------->\n\nWhat made u think that resultant can be in diff. direction\nEven try using the triangle law .It gives the same result.
614422
Depends what information you already have. The simplest one I can think of is:\n\nVelocity = Acceleration x Time\n\n-Therefore-\n\nAcceleration = Velocity / Time\n\nBut you might have other variables involved here.
448815
Do you mean a motion in parliamentary procedure?\nDo you mean motion as in physics?\nIn physics it is velocity relative to a plane of reference.\nYou measure it by determining the position of the item at two different times and then dividing by the difference in time.  So you get units of distance per time - velocity.\nLike miles per hour or feet per second or meters per second.
1110309
The Rate of change of momentum of a body is equal to the resultant force acting on the body, and takes place in the direction of the force.\n\nMomentum = mass * velocity\n\nThe masses are the same on Earth and the moon.\n\nMomentum would be equal!
733773
Zero.  If the velocity is constant, acceleration is 0.
844762
There are jthree  formulae cncerning velocity.These are v=u+at , V^2=u^2+2as ,and s=ut +(1/2) at^2 ,where u= initial velocity,v=final velocity ,a=accelaration.,s= distance travelled and t= time.Now how to decide which formula is to be used?in the problem,just see what they want you to find out and note down what is are already given in the problem, if they give you u,a and t and ask you to find out v,apply formula no.1.But if they gdonot give you time but give the distance or displacement and asks you to find v,donot hesitate to apply formula no,2 and so on.if you have any difficulty to understand.please do not hesitate to write to me through yahoo answersand i shall be glad to assist you
573522
kinetic energy is 1/2 mv² so it depends on mass and velocity
954123
The Reynolds number is an adimensional value. It is calculated by:\n\nRe = (d*v*L)/ u\n\nwhere v stands for velocity.\n\nTherefore, the Reynolds number is proportional to the velocity! So the higher the velocity the higher the Reynolds.\n\nThe other letters: d stands for density, L for a characteristic length and u is the viscosity
86843
Corresponding to the definition:\n\nav=deltaX/deltaT\n\nWhere av is average velocity.\n\nSo because of deltaX being zero, av is Definitely zero
820794
Horizontal velocity is the speed of something flat ot the ground like a car on the road.\n\nVertical velocity is the up/down speed, like a ball thrown straight up.\n\nIf you throw something on an angle (not straight up) it has some vertical velocity in the up direction and some horizontal velocity along the ground.
495016
This is more of a physics question...\nd final = .5*a*t^2 + v*t + d\nv final = a*t + v\nd is displacement, v is velocity, a is acceleration.\nEnjoy.
212257
velocity is always the motion of an object between two points. you can measure the velocity of planets, stars, solar systems, galaxies, but the absolute of the universe cannot be determined since there are not objects to reference its motion to. The universe is expanding but this is unrelated to the motion of the universe since it is expanding equally in all directions.