1
   

Why do people think that rockets work in the vacuum of space?

 
 
fresco
 
  1  
Reply Sun 28 Apr, 2019 12:27 am
@Brandon9000,
What the OP shows ignorance about is the necessity for the maximum generality of a concept for its adoption in science. The concept of 'pressure gradients' might be useful in limited contexts (in meteorolgy for example), but Newton's laws are more fundamental, and work in all contexts.
Its 'Scientific Method 101', flunked by most attention seeking dissenters!
BTW Mark Noble is here merely to do a bit of kibbitzing, by his own admission.
Brandon9000
 
  0  
Reply Sun 28 Apr, 2019 08:01 am
@fresco,
fresco wrote:
What the OP shows ignorance about is the necessity for the maximum generality of a concept for its adoption in science. The concept of 'pressure gradients' might be useful in limited contexts (in meteorolgy for example), but Newton's laws are more fundamental, and work in all contexts.
Its 'Scientific Method 101', flunked by most attention seeking dissenters!
BTW Mark Noble is here merely to do a bit of kibbitzing, by his own admission.

True and well put.
0 Replies
 
mark noble
 
  1  
Reply Sat 4 May, 2019 05:54 am
@Brandon9000,
It's vague, to some. And vivid, to some.
Where would you like to begin?

Ask one question at a time, please?
0 Replies
 
farmerman
 
  1  
Reply Sat 4 May, 2019 08:32 am
@fresco,
why the hell is this thread even necessary? Its the end of Western Civilization when we have to tell people not to stand behind a jet engine or dont eat detergent "balls"
fresco
 
  1  
Reply Sat 4 May, 2019 09:26 am
@farmerman,
That's the million dollar question...'Why is a thread necessary'. Smile
The answer ranges from genuine enquiry to 'graffiti wall' for misfits.

BTW Is it St. Maarten where fools line up along the runway fence to get the jet blast ?
mark noble
 
  1  
Reply Sat 4 May, 2019 09:33 am
@fresco,
St martin's?

Pulp - DISCO 2000?
0 Replies
 
Beaker17
 
  1  
Reply Fri 13 Sep, 2019 08:51 am
What an elementary question,
Rockets don't get thrust by pushing against the air. Rockets get thrust by pushing against the rocket on one side and pushing against nothing on the other side of an explosion.
maxdancona
 
  1  
Reply Fri 13 Sep, 2019 08:58 am
@Beaker17,
I would say they are pushing against the gas being expelled from the rocket.
0 Replies
 
Beaker17
 
  1  
Reply Fri 13 Sep, 2019 09:07 am
Newton's 3rd law of Motion -
"For every action, there is an equal and opposite reaction."
It is the reaction against the rocket from the explosive propellant combustion
that provides acceleration to the rocket mass. Nothing at all to do with exhaust gases.
maxdancona
 
  1  
Reply Fri 13 Sep, 2019 09:12 am
@Beaker17,
I taught Physics. You are wrong.

There is a force being exerted on the gas. This results in the gas accelerating and gaining momentum.

The force being put on the gas is exactly equal and opposite to the force accelerating the rocket forward.

https://en.wikipedia.org/wiki/Working_mass
Beaker17
 
  1  
Reply Fri 13 Sep, 2019 09:16 am
@maxdancona,
I rest my fundamental case - have it your way.
My condolences to your students.
maxdancona
 
  1  
Reply Fri 13 Sep, 2019 09:34 am
@Beaker17,
Beaker17 wrote:

I rest my fundamental case - have it your way.
My condolences to your students.


It is not just my students... it is every high school and University student in the world. I am just teaching the same Physics that is taught everywhere.

I sure hope the entire Physics community listens to you.
farmerman
 
  1  
Reply Sat 14 Sep, 2019 09:34 pm
@maxdancona,
Your arguing with a budgie
0 Replies
 
 

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