It's been more than two months now, sceptimatic; in case you forgot, you promised to explain how you arrived at the conclusion below. To jog your memory, in the conversation that followed, it came to light that you knew this took 8 minutes, somehow involved the distance travelled, and was very amusing [no one seems to doubt this]. We're still waiting.
It should be pretty obvious to you that a shuttle launching into so called space, supposedly attaining a speed of 17,000 mph, would have to accelerate at a 5 miles per second per second to attain this 17,000 mph speed.
Do you under stand what this means?
Or have you recognized your mistake yet (I'm betting on the obvious rookie error) and just hoping this will be forgotten?
There is no mistake. If the shuttle is to attain that speed then what I said has to happen. There's no other way for vertical flight.
It's not a case of acceleration over distance. It's immediate acceleration and a constant until the fuel is used. It has to be 5 miles per second per second.
"That speed" - do you mean 17,000 mi/hr as first stipulated? What has to happen to attain that speed? 5 mi/sec2 for eight minutes? Why? Please show your math. Why does the direction - vertical or horizontal matter?
If you accelerate at a constant 5 mi/sec/sec how fast will you be going after four seconds? How fast after 8 minutes?
There is no other way it can work on vertical flight. It would be different if it was on horizontal flight with wings.
You won't grasp this because your mind is focused on the rocket kicking itself up its own arse. This is why you people will always have a head full of crap calculations and no logical thought.
Acceleration is acceleration, no matter what the method of propulsion is. How do wings supply acceleration?
It doesn't matter what direction the acceleration is, the results are the same.
I'm still betting on the rookie error for where that 5 mi/sec2 came from.
You're smart but as naive as hell.
You may be right about the naive part - I'm here, aren't I? That may suggest otherwise about being smart, too. Whatever. It's always good to see a different perspective and I have learned some things in my time here, so it's all good.
Observe what I type.
Naturally the speed of the rocket is bullshit, so let's get that out in the open.
You were the one that brought it up in the first place, but it sounds about right for LEO.
Assuming we accept the fantasy as real then the rocket has to IMMEDIATELY accelerate to 17,000 mph from the immediate lift off.
That
is fantasy and I don't accept it. To do that would require infinite acceleration, which would require infinite power, which is clearly impossible. It's not necessary in real-world launches. Why would you have to have terminal velocity off the pad?
It can NOT gain acceleration vertically.
If thrust exceeds weight it will accelerate vertically.
5 miles per second times by 8 minutes or 480 seconds means an altitude of 2,400 miles?
I asked how fast, not how high, and that answer is wrong, anyway.
The acceleration is 5 mi per second
per second.
The answer to the question I asked is 2400 mi
per second.
v = at (velocity is acceleration times time)
= (5 mi/sec
2)(480 sec)
= 2,400 mi/sec.
Assuming it went straight up the whole time, the altitude would be
s =
1/
2at
2 (distance is one-half acceleration times time squared)
= (5 mi/sec
2)(480 sec)
2/2
= (5 mi/sec
2)(230,400 sec
2)/2
= 576,000 miles
Fortunately, we
don't need to accelerate at this rate!
It naturally is bullshit. Don;t even dare pretend that it gains acceleration as it climbs. why?
Observe what I type.
Your rocket has to use full thrust to get off the launch pad. It's at it's ultimate strength of push and can only keep that or lose it. It cannot increase it.
Maximum thrust getting off the pad is a reasonable assumption and probably true enough in most cases. The thing is, if going straight up the whole time, a rocket's acceleration will be proportional to the amount its thrust exceeds its weight. As it burns fuel, its
weight decreases, so if the thrust remains constant, the
acceleration will increase. If it has enough thrust to leave the pad, at maximum weight, it will accelerate at a greater rate as it climbs under constant thrust because it's getting lighter.
Observe why I say this as it applies to all life making a vertical movement whether it's an organism jumping ot a mechanical device under energy of whatever powers it. VERTICALLY.
VERTICALLY. OK?
Bend down and spring up. Where is your maximum thrust to lift your body?
Can your body gain in momentum after you have used full thrust, vertically?
A bow and arrow. When is that arrow at it's optimum power and can it gain in power once released?
None of them are under constant energy applied so both will utilise the full power and lose it the second it's released, vertically.
Also guns. In a gun, the projectile will be accelerated by the force of the burning powder until it leaves the barrel; after that, the powder can no longer provide an accelerating force.
All this is true, but these aren't rockets. Rockets continue to provide thrust after they've left the pad.
Firework rocket. Light the fuse and it lifts off at super speed and keeps it until it uses up it's fuel. It does not gain by acceleration except the immediate accelerated launch, vertically.
This is not necessarily true. Have you studied this to draw your conclusion?
A rocket will expend all of its fuel as fast as it moves and will fall to Earth in very short order, mostly after powered VERTICAL flight of around 30 seconds or less. Some maybe a little more.
Where did this 30 seconds (or so) come from? Did you make it up?
No vertical rocket is going to burn for any 8 minutes. It's impossible and you should know why.
I don't know if it is impossible or not, but don't see any reason why it should be impossible in principle. Even if it
is impossible in practice, since real rockets don't lift off and go straight up for 8 minutes, it doesn't matter.
Not convinced are you?
Nope.
You can't grasp it because your mind is based on fantasy science.
I can't grasp it because what you're saying is nonsense.
Get in your var and go and negotiate a steep hill.
Your best chance of getting up that steep hill is to put it in first gear and press that foot pedal to the floor.
Will you accelerate up that hill? no. You will immediately accelerate and then your car is either expending all its fuel keeping a steady run or it slows and claps out.
How long you can accelerate uphill depends on three basic things: how much power is available, the mass of the car (how much it weighs), and how steep the hill is. There's also aerodynamic drag (considerable if you're going fast enough) and a few odds and ends like friction we will neglect here. The car getting lighter as you use up the fuel is also ignored here; this is a small effect in a car, where the weight of the fuel is a small fraction of total vehicle weight and changes slowly, but a very significant consideration with rockets since the fuel is a very large part of its initial mass, and can be shed very quickly.
Power is the ability to do a given amount of work in a given amount of time. Doing the same work in less time requires more power, doing more work in the same amount of time requires more power. "Work" in this context is lifting the weight of the car to higher elevation by driving uphill.
If you're accelerating from a stop at the bottom of a hill, your speed is slow at first so you start gaining elevation slowly, so the power required is relatively low. As you accelerate, the power required increases because you're climbing a greater distance (doing more work) in a given amount of time. Eventually you will reach the maximum power your engine can produce and you can no longer accelerate going uphill - but you can maintain that speed if the hill maintains the same slope.
Get this stupid 17,000 mph crap out of your head and gather some logic. You have been filled full of crap your whole life and this is just one part of it.
You were the one who brought up 17,000 mi/hr.
Wake up before you expire in total ignorance.
Back atcha.