Rocket Launch relativity (1 Viewer)

[CrashOveride]

it says here that when u launch a rocket in the direction of its rotation, the rotational velocity of the launch site relative to the sunn will add to the orbital velocity of the rocket relative to the Earth, to produce a higher orbital rocket velocity relative to the Sun

how is it relative to the earth? i mean the earth is rotating already so relatiive to earth its only what the rocket velocity is from its engine?

 

[gordo]

the earth is rotating on its axis
so if u launch with the roatation of the earth, then relative to the earth u are going slower than if u launch against its rotation

that has no relevance for rocket lanuches cause u would do it the other way because the rocket is already moving with the earths rotational velocity.

but relative to the earth, if u launched int he opposite direction to its rotation u would be going faster relative to it

 

[Jase]

Yes.. 'relative to earth' just means the rocket power.

That point is just worded really stupidiotly.

 

[CrashOveride]

ok i can see that, but when we launch with the rotation and we want relative velocity, if u use vector addition, well subtraction in this case, the rocket relative to the earth is just whatever the rocket velocity is right? if it went against the rotatioin, then it would be rocket v - (- earth rotation) so rocket+earth rotation so yes it wud be faster relatively. My point is that the book says when u launch with the rotation you gain velocity relative to the earth? But because ur going in the direction of that rotation, i dont think thats the case, its velocity only gained rel. to sun ?

 

[Shuter]

Remeber velocity has direction.

I believe they're implying velocity as being in the direction of the earth's rotation. You do this as you will be spinning faster thus easier to overcome gravity and leave. Going the other way, you will infact be going faster relative to earth in a spinning sense, but not in the way which is actually useful to be going.

 

[CrashOveride]

if u launch with the earth, ur direction is obviously with the earth. so ur direction is the same as the earth. now, coming back to it, how is that relative motion with the earth? the claim is that the earth's rotation gives the rocket a boost relative to the earth (its clear its boost is valid relative to the sun).

 

[einsteinthe2nd]

Yes, when launched into the east (the direction the earth rotates) a boost will be provided relative to the SUN. Relative to the Earth, would just be the rockets velocity. Just think of it this way, someone on Earth with a radar gun points it at the rocket, they will read it as its veloctiy (relative to the Earth)....Say 1100km/h. If you were on the sun with a radar gun, besides being completely incinerated, you would notice that the velocity is that of the earths ROTATIONAL velocity + that of the actual rocket........uhhhh



I just confused myself.........

 

[CrashOveride]

yeah thats what ive been saying...but Jacaranda thinks otherwise.... ? :/

 

[einsteinthe2nd]

I got Jacaranda here, and it says relative to the sun.........Remninds me of Pink Floydd

The sun is the same in a relative way....

 

[CrashOveride]

yes it says relative to the sun, but it also says it gains velocity relative to the earth due to the earth's rotation...which is the confusing part