Young Aussie genius whipping NASA in Moon Hoax Debate!

reply to post by Aloysius the Gaul

Thanks..Always good to learn..

So if you give him a ball on the moon that is 6 x the mass on one on the earth he will think the weight is the same, but he will only be able to give it 1/6th the acceleration of the smaller one, regardless of whether he is on th earth or the moon.

HOWEVER....what you may be being confused by is how far the ball will travel on the moon vs on earth.

No, I was not confused by distance..
I used baseball as an example because over the short pitching distance there is minimal vertical movement..
It also doesn't affect velocity..

reply to post by backinblack


It is somewhat counterintuitive because here on the surface of the earth, we consider weight and mass to be one and the same. But if you think about it, "weight" is directed straight down. When a pitcher is throwing the ball, the effort he puts into it isn't fighting against the ball falling down... It's into moving the ball forward.

Originally posted by nataylor
reply to post by backinblack

 

It is somewhat counterintuitive because here on the surface of the earth, we consider weight and mass to be one and the same. But if you think about it, "weight" is directed straight down. When a pitcher is throwing the ball, the effort he puts into it isn't fighting against the ball falling down... It's into moving the ball forward.

So a ball with six times more mass that weighed the same as a lighter ball on earth could only be pitched at about 17mph rather than the 100mph of a normal ball on earth...?

reply to post by backinblack


Yup. A baseball is about 5-5.25 ounces. So 6 times that would be 30-31.5 ounces Try throwing a nearly two-pound ball. It'd be hard.

Originally posted by nataylor
reply to post by backinblack

 

Yup. A baseball is about 5-5.25 ounces. So 6 times that would be 30-31.5 ounces Try throwing a nearly two-pound ball. It'd be hard.

Weird huh?
And yet if you pitched upwards then you could pitch the 30 ounce ball at 100mph?

reply to post by backinblack


No. You could pitch a regular baseball straight up at 100 mph. The speed at which the ball leaves the pitcher's hand is directly proportional to the mass of the ball, regardless what direction it is thrown.

Originally posted by nataylor
reply to post by backinblack

 

No. You could pitch a regular baseball straight up at 100 mph. The speed at which the ball leaves the pitcher's hand is directly proportional to the mass of the ball, regardless what direction it is thrown.

lol, sorry I don't buy that one..
Great debate this...
I see no reason why the vertical movement of his arm would not match that of a six times heavier ball on earth, given that it weighs 1/6 on the moon..

Edit: I did do physics in school..
What you are doing is not putting in all the components..
The formula is F=MA....
In a vertical throw the F=pitcher's arm speed MINUS the force of gravity..
On the moon the force of gravity is less so arm speed (F) is increased ..

reply to post by backinblack


This is a basic tenant of Newtonian Physics. F=ma. The acceleration you can impart to an object is directly proportional to to the force you exert on it and the mass of the object.

Let's do the math. The maximum height of an object launched upwards (d) is equal to the initial velocity squared (v^2) over two times the acceleration of gravity (2g), or d=v^2/2g.

On earth, g is 9.8 m/s^2. 100mph is 44.704 m/s. So on earth, the height of a ball thrown upwards at 100 mph would be (44.704^2)/(2 * 9.8) or 101.96 m.

On the moon, g is 1.63 m/s^2. So the height would be (44.704^2)/(2 * 1.63) or 613.02 m.

You'll notice that the height is 6 times as high on the moon, exactly as we'd expect. And the initial velocity of the ball was the same in both cases.

If, as you suggest, the velocity of the ball was 6 times as high on the moon, you'd have an initial velocity of 268.224 m/s. So the height would be (268.224^2)/(2* 1.63), or 22,068.75 m. That's a whopping 216 times higher than on earth. So, as you can see, that can't possibly be correct.

reply to post by nataylor

If, as you suggest, the velocity of the ball was 6 times as high on the moon, you'd have an initial velocity of 268.224 m/s. So the height would be (268.224^2)/(2* 1.63), or 22,068.75 m. That's a whopping 216 times higher than on earth. So, as you can see, that can't possibly be correct.

No, because it's still limited by arm speed..

Originally posted by backinblack
No, because it's still limited by arm speed..

You're confusing mass, which is a property of an object, with weight, which is a force applied by an object.

The easiest way I have found to describe this is to imagine the amount of effort you would have to put in to change the velocity of an object by 1 metre per second. The object contains the same amount of stuff, with the same amount of energy, whether it is on the moon or the earth. No matter where it is, you still have to put in enough energy to accelerate all of its mass.

On the other hand, weight is a force applied by that mass in a specific direction (straight down). This is why in nataylor's example, the ball travels much further, rather than being thrown much faster. The amount of force that can be applied is the same in both cases, and the mass is the same in both cases, so the acceleration must be the same.

What is different is that as the ball is thrown vertically, it has 1/6th the amount of force pulling it back down to the ground, and so it will lose speed much more gradually.

The only force reduced on the moon that is relevant is friction, and JW seems to try and address this by increasing the volume of his moon rock, and thereby the surface area. However, both friction and pressure increase with the square of the area, and they cancel each other out, so in no sense does his analysis hold up. If you add in friction, any advantage vanishes, and if you know the difference between mass and weight, it was never there to begin with.

reply to post by backinblack


Not sure what you mean. At what sped would you expect the ball to leave the pitcher's hand on the moon? I though you wre arguing it would be 6 times the speed of what the pitcher could do on earth.

Originally posted by nataylor
reply to post by backinblack

 

Not sure what you mean. At what sped would you expect the ball to leave the pitcher's hand on the moon? I though you wre arguing it would be 6 times the speed of what the pitcher could do on earth.

No, a pitchers arm speed is constant..
I was just saying he could throw six times the mass at the same arm speed in a vertical direction..
I still don't see why that is not true..

reply to post by exponent

You're confusing mass, which is a property of an object, with weight, which is a force applied by an object.

The easiest way I have found to describe this is to imagine the amount of effort you would have to put in to change the velocity of an object by 1 metre per second. The object contains the same amount of stuff, with the same amount of energy, whether it is on the moon or the earth. No matter where it is, you still have to put in enough energy to accelerate all of its mass.

OK..Hows this..
On earth there is no way an average person could pick up say a 50kg ball and toss it in the air, ie; impose velocity/acceleration on the ball..
On the moon you could..So your concept doesn't fit..
As I said, you need to take into account gravity in your F=MA equation..

Originally posted by backinblack
No, a pitchers arm speed is constant..
I was just saying he could throw six times the mass at the same arm speed in a vertical direction..
I still don't see why that is not true..

I don't know how to explain it more simply.

I've shown that to throw a ball 6 times as high on the moon, which is the height we expect with 1/6 gravity, you need to have the same initial velocity on the earth and moon. Since F=ma, to get the same amount of speed out of a ball with 6 times the mass, you'd need to exert 6 times the force. If he could generate 6 times the force, that means he would be able to throw a regular baseball with 6 times the speed. But if he could do that, then he could throw the ball straight up to a height of over 22 km. We know that's not possible.

reply to post by nataylor

I don't know how to explain it more simply.

Neither do I Nat..

You MUST take into account ALL forces acting on the mass...
Gravity is a force which is opposing the upward force and thus MUST be included in your F=MA..

If gravity is 1/6 then it WILL affect the resulting acceleration/velocity..

Originally posted by DJW001
reply to post by FoosM

 

I would even say that mass can change and does change in space or on the moon.
That is, if we actually knew what mass really was.

Mass is the amount of "stuff" in something. Now you know what it is.

I know what it means,
Im saying from what I understand the concept of what "mass" is still misunderstood.

Originally posted by backinblack
reply to post by nataylor

 

I don't know how to explain it more simply.

Neither do I Nat..

You MUST take into account ALL forces acting on the mass...
Gravity is a force which is opposing the upward force and thus MUST be included in your F=MA..

If gravity is 1/6 then it WILL affect the resulting acceleration/velocity..

Thats what Im wondering too, I thought mass affected gravity or something in that order.

Originally posted by exponent

Originally posted by FoosM
Why would they have to have craters in their footage?
Maybe you have a hard time grasping the idea of lying to the public?

Why would they lie about something which was empirically determinable? That would be as stupid as lying about the speed of light. Do you think NASA just lied for no reason whatsoever? Maybe for fun?

The only way anyone could counter NASA's claims what the moon is like is to go there themselves. Guess what, to this day nobody has. NASA would have known how impossible it be for any nation to do so. Their only competition was Russia, and they quickly partnered with them didnt they.

I can claim leprechauns with pots of gold live in my house, but as long as you dont get to go in my house to see them, I wouldn't blame you for being skeptical.

Nobody has never sent anything like a LEM to land on the moon to see if craters would truly be made. For that matter, when is the last time a probe was sent to land? Why are they only orbiting or crashing objects on the moon?

Why is manned space exploration dead? And dont tell me due to lack of public interest because that has never been a factor proven by studies. It has only served as a an convenient excuse. I'll tell you, it was dead before it even got started. We haven't conquered anything above LEO.

reply to post by FoosM

I can claim leprechauns with pots of gold live in my house, but as long as you dont get to go in my house to see them, I wouldn't blame you for being skeptical.

On the other hand, if there were extensive reports of your leprechaun infestation from all of your neighbors, abundant photographs, live television coverage and living leprechauns sent to leading scientists all over the world who were able to examine them and confirm that they were leprechauns, I'd have to be a close minded bigot to reject the possibility completely, don't you think?

reply to post by DJW001

On the other hand, if there were extensive reports of your leprechaun infestation from all of your neighbors, abundant photographs, live television coverage and living leprechauns sent to leading scientists all over the world who were able to examine them and confirm that they were leprechauns, I'd have to be a close minded bigot to reject the possibility completely, don't you think?

And what evidence actually came from anybody but the original source, NASA???