Donald Trump expected to slash Nasa's climate change budget in favour of sending humans back to the

originally posted by: raymundoko
a reply to: InachMarbank

It's not falling for all intents and purposes as it's forward momentum overcomes the gravitational force. As long as the forward momentum doesn't slow significantly The inertia is overcoming gravity that is acting on the moving object.

Think of it like this. The satellite is a projectile moving in a straight line. The centripetal force causes that line to curve towards the earth as it pulls the object "downward". This does NOT cause acceleration as the object never actually "falls". If the object were much faster, it would eventually overcome gravity and be slingshot into space, much slower and it's orbit would decay and it would slowly fall to the planet of the course of however many orbits and burn up in the atmosphere. The tangential velocity of the object keeps it in a relatively circular orbit.

I have seen that centripetal force... explanation... before and it is still making me scratch my head...

To illustrate I have tried to take it into consideration, here is where I think you are heading...

formula for centripetal force is F = m*v^2/r

formula for the force of Gravity is F = GMm/r^2

"If those two forces are equal and opposite you will have a circular orbit."

we can simplify that to:

v^2/r = GM/r^2.

solve for v

v^2 = GM/r

v = SQRT(GM/r)

v = 17,241 mph

This seems to be the formula NASA has used to derive their "speed needed" for the ISS to stay in orbit.

The part that's making me scratch my head is:

"If those two forces are equal and opposite you will have a circular orbit." (centripetal force and gravity)

Centripetal force is not the opposite of gravity, right?
Centripetal force is the same as gravity, right?
So the entire assumption for the formula is incorrect, right?

More cognitive dissonance shellacked on heavy...

"It's not falling for all intents and purposes as it's forward momentum overcomes the gravitational force."

This is inconsistent with Isaac Newton's 17th century, "thought experiment," the common explanation I have read for how a satellite orbits.

What's the deal?

a reply to: InachMarbank

It *can* be gravity. It could also be a string, or your arm swinging a bucket...

A sling for example uses centripetal force to increase the velocity of the projectile that is being acted on by centrifugal force when it's finally released.

I don't understand how you think it violates newtons cannonball thought experiment. That's where orbital velocity came from basically.

The tangential velocity for low earth orbit is about 17k mph.

originally posted by: raymundoko
a reply to: InachMarbank

It *can* be gravity. It could also be a string, or your arm swinging a bucket...

A sling for example uses centripetal force to increase the velocity of the projectile that is being acted on by centrifugal force when it's finally released.

I don't understand how you think it violates newtons cannonball thought experiment. That's where orbital velocity came from basically.

The tangential velocity for low earth orbit is about 17k mph.

An example that came to my mind is water skiing.

You can slalom ski, zig zag from side to side, outside the wake of a boat, to increase your speed.

Say you are skiing behind a boat moving 30 mph forward.
And say, with the string dragging you, you can slalom 20 meters from side to side, and it takes you 5 seconds to go from the farthest left, to the farthest right. This is 9 mph sideways.
30 mph forward plus 9 mph sideways, brings total speed to 39 mph.

If you say the tangential speed of the ISS is 17000 mph,
like the water skiing example,
what is the forward speed, and what is the down speed, to give this net speed of 17000 mph?

originally posted by: Christosterone

The two greatest achievements in the history of mankind were splitting the atom and walking on the moon…first achieved in 1969 by the United States of America....

Not to dampen your enthusiam, but wanted to point out that (i) "splitting the atom" was the work of a New Zealander heading up a team in the UK, while (ii) "putting man on the moon" was the result of the work of Werhner Von Braun, a German who developed much of the technology needed whilst building bombs for Hitler.

The US is great at bringing teams of the best and brightest together, bankrolling them, and giving them the independence to innovate and encouragement to think big. That seems to be Trump's method as well. That bodes very well for the next four years.

a reply to: InachMarbank

The ISS isn't doing that though. It's flying in a straight line. Gravity acts as a string that causes the centripetal force. No tension is being added to or released from said force which means the speed is an almost constant.

I have to ask though, because this concept isn't very hard to wrap your head around, what is your angle? What do YOU believe concerning satellites? Do you think they aren't up there? Something seems off with your line of questioning.

originally posted by: raymundoko
a reply to: InachMarbank

The ISS isn't doing that though. It's flying in a straight line. Gravity acts as a string that causes the centripetal force. No tension is being added to or released from said force which means the speed is an almost constant.

I have to ask though, because this concept isn't very hard to wrap your head around, what is your angle? What do YOU believe concerning satellites? Do you think they aren't up there? Something seems off with your line of questioning.

If the concept is easy, how come nobody can seem to define the 2 variables specifically?

1. What is speed forward?
2. What is speed down?

You answered only 1 speed, right?
Tangential speed of 17000 mph.
And said speed down is almost constant.

If the speed down is constant, what is the constant speed?

I am still trying to figure out what to believe.

We seem to have strayed from the OP somewhat. Trump doesn't know what goes on at Groom Lake, and NASA unveiling the same old 'new' drive system every 5 years has gone beyond passe' it's pathetic.

1 gram of thrust per kilowatt? A bloody lifter does 1000x better than that on less than 12 watts, and most of THAT is discharge leakage, not contributing to the Biefeld-Brown effect.

I can accelerate 50 grams using about 6 watts, using materials that work in a vacuum, and because you are in a vacuum, discharge leakage & resistance drops down to almost zero. This means you can ramp up the voltage & magnetic fields to vast proportions, and that means you can go any speed you want.

So here's a question for you all, how long would it take to design & build an electrically driven craft that would make NASA's efforts look like the Flintstones?
And how much would it cost?

(Elon, Sir Richard et al, feel free to call me)

a reply to: InachMarbank

No I said the speed is constant, not the down speed. There is no down speed as the forward momentum overcomes the force of gravity. All we have is a constant centripetal force that neither adds or releases "tension", hence the elevation is an almost constant. It neither had a "down" or an "up" speed, just a "forward" speed.

All that is happening is a forward moving projectile is being guided along a path by a central string.

You are confusing a centripetal force with "falling".

originally posted by: raymundoko
a reply to: InachMarbank

No I said the speed is constant, not the down speed. There is no down speed as the forward momentum overcomes the force of gravity. All we have is a constant centripetal force that neither adds or releases "tension", hence the elevation is an almost constant. It neither had a "down" or an "up" speed, just a "forward" speed.

All that is happening is a forward moving projectile is being guided along a path by a central string.

You are confusing a centripetal force with "falling".

Well, perhaps you can see why I might get confused by your explanation...

Here is a standard answer from a Q&A article for how the ISS stays in orbit:

"the space station is ALWAYS FALLING but never hitting the ground."

"In its orbit, the station also has inertia that causes it to tend to move in a straight line away from Earth. However, it is also subject to the force of gravity. It is pulled toward the center of the planet. This force is at a right angle to its inertial motion so it does not change the forward motion. It does PULL THE SPACE STATION DOWNWARD, just like any other falling object. While gravity is PULLING DOWNWARD, the tendency to move in a straight line would carry it away from Earth. As a result, the space station is ALWAYS FALLING but always the same distance from the surface."

"Because the space station and everything in it is FALLING freely, people inside it experience weightlessness."

"Think about DESCENDING in a very fast elevator. The floor of the elevator is dropping rapidly so the sensation of weight is reduced. You feel almost as if you were able to float."

www.idiotsguides.com...

Are you saying the ISS is not falling as explained in this Q&A?

a reply to: InachMarbank

They are attempting to make it easy to understand. It has no downward speed but it's falling due to the centripetal force. That's what an orbit is. The centripetal force, caused by gravity in this case, constantly pulls the forward moving object to the center at the same rate; Hence there is no "downward speed", just a "forward speed". That "forward speed" is also the "falling speed".

They are called vectors, gentlemen.

Centripetal force does not really exist, it's purely Earth's gravity versus the velocity & direction of the ISS.

In time, unless they fire the rockets now & then, the station will slow down enough for it to fall back down.

Incedentally, the moon is actually getting further away, about 1-2 cm a year.

So either it is speeding up in it's orbit (highly unlikely) or it is getting lighter.
I.E. someone is mining it.

Science 101, padawans

a reply to: playswithmachines

it's purely Earth's gravity versus the velocity & direction of the ISS.

That's called centripetal force...

a reply to: raymundoko

Yes, and it's an imaginary force. There is only the gravity of the earth (and the ship) and the ship's momentum, which is a product of it's mass and velocity. A vector is the sum of the 2 forces acting on the craft.

If you get it right you can put something in orbit. For a while.

a reply to: playswithmachines

Gravity is not an imaginary force...

I think you are cunfusing what centripetal force is. In this case it IS gravity. It's not imaginary at all. It's only imaginary in that it can be any force acting on the object in relation to a wheel/circle.

Forward motion combined with the centripetal force of gravity allows the object to stay in orbit.

physics.stackexchange.com...

originally posted by: raymundoko
a reply to: InachMarbank

They are attempting to make it easy to understand. It has no downward speed but it's falling due to the centripetal force. That's what an orbit is. The centripetal force, caused by gravity in this case, constantly pulls the forward moving object to the center at the same rate; Hence there is no "downward speed", just a "forward speed". That "forward speed" is also the "falling speed".

How does an object fall but have no downward speed?
If the forward speed is also the falling speed, like you say, are you saying the ISS is falling 17000 mph?

a reply to: InachMarbank

President Trump ...


We Will Go to Mars , Not Because it will be Easy , but Because it will be Hard . Oh , and Did I Mention the Other HUGE Things ?

originally posted by: Zanti Misfit
a reply to: InachMarbank

President Trump ...


We Will Go to Mars , Not Because it will be Easy , but Because it will be Hard . Oh , and Did I Mention the Other HUGE Things ?

Uh, is that your letter to Trump?

a reply to: InachMarbank

No , it was a Play on a JFK Speech in 1962 . You didn't " Get It " I see..........

originally posted by: raymundoko
a reply to: playswithmachines

Gravity is not an imaginary force...

I think you are cunfusing what centripetal force is. In this case it IS gravity. It's not imaginary at all. It's only imaginary in that it can be any force acting on the object in relation to a wheel/circle.

Forward motion combined with the centripetal force of gravity allows the object to stay in orbit.

physics.stackexchange.com...

Didn't Isaac Newton believe gravity was a spirit pushing down on Earth?

originally posted by: Zanti Misfit
a reply to: InachMarbank

No , it was a Play on a JFK Speech in 1962 . You didn't " Get It " I see..........

Ah ok. Haha.