Mythbusters plan to uncover plane on conveyor belt

91,210 Views | 2087 Replies | Last: 5 yr ago by toucan82
Texaggie7nine
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:19p, 1/31/08
quote:
It is not possbile for the plane's speed to be relative to the conveyor belt's speed.


If you draw a dot on the belt. You can measure the speed at which the plane is moving away from that dot. This is why I have been saying the speed in relation to the belt's direction.

Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:26p, 1/31/08
AG
OK, let me rephrase this one last time. You're right, there is a relative speed of the plane to the conveyor belt. But this has, except for a completely negligable amount of friction, absolutely no effect on the speed of the plane relative to the ground.
Reply Quote
TexasRebel
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:32p, 1/31/08
AG
unless the conveyor is traveling at 6 lyps

but then you get into the whole time travel thing...
Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:33p, 1/31/08
AG
Thus my disclaimer, Rebel.

[This message has been edited by Red Skye (edited 1/31/2008 6:34p).]
Reply Quote
jokershady
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:34p, 1/31/08
AG
jesus tap-dancing christ!

let this thread die already!

Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:35p, 1/31/08
AG
We're more than halfway to 100. We can't let it die now.
Reply Quote
jokershady
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:36p, 1/31/08
AG
Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:37p, 1/31/08
TexasRebel
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:38p, 1/31/08
AG
the saddest part is:

videoag98 reneged on his promise to quit at 200,000 views on the original thread...

well...who's attempting to quit this time?





































































not it!
Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:42p, 1/31/08
AG
I'm in it for the long haul.
Reply Quote
Texaggie7nine
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
6:47p, 1/31/08
quote:
But this has, except for a completely negligable amount of friction, absolutely no effect on the speed of the plane relative to the ground.


I'm not arguing that it does. I'm arguing that the wording makes a world of difference.

If the plane is traveling away from the direction of the belt at the same speed the belt is moving, then the plane is stationary. Forget the logistics of how it is that way, we are talking about the actual statement.



[This message has been edited by Texaggie7nine (edited 1/31/2008 6:48p).]
Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
7:14p, 1/31/08
AG
quote:
If the plane is traveling away from the direction of the belt at the same speed the belt is moving, then the plane is stationary. Forget the logistics of how it is that way, we are talking about the actual statement.

No it's not stationary. The plane will never be stationary. It is impossible for the plane to be stationary, no matter how you word the problem.
Reply Quote
kraut
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
7:28p, 1/31/08
AG
http://www.youtube.com/watch?v=siYQU99VaAM

Free body diagram.
Reply Quote
91_Aggie
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
7:30p, 1/31/08
AG
quote:
If the plane is traveling away from the direction of the belt at the same speed the belt is moving, then the plane is stationary. Forget the logistics of how it is that way, we are talking about the actual statement.


Wow! I can see someone getting caught on the semantics of the way the problem was worded, but to still believe the above at this point is ludicrous.

If you can't understand that the speed of the conveyor belt has no real effect on the plane's ability to move forward then I don't know what can be done to convince you.
Reply Quote
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:01p, 1/31/08
What if the plane had no wheels, and was nothing but a big heavy block of wood?
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:17p, 1/31/08
AG
quote:
Unless it can generate enough thrust to go ballistic, but even that is flawed since the engines would have to be facing up.


The plane I spent this afternoon working on could take off from the conveyor belt easily...since it CAN point the engines up...

Until it wants to go fast and then points the engines forward...

I got my HQ engineer's stomach all queasy, too...
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:17p, 1/31/08
AG
quote:

What if the plane had no wheels, and was nothing but a big heavy block of wood?


It would have the flying qualities of an F-4 with both engines out????/
Reply Quote
OneManArmy
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:24p, 1/31/08
quote:
If the plane is traveling away from the direction of the belt at the same speed the belt is moving, then the plane is stationary. Forget the logistics of how it is that way, we are talking about the actual statement.


If you look at it this way you are assuming that the plane is only providing enough forward thrust with its engine to counteract the rolling friction of the wheels. That is a pretty stupid assumption.
Reply Quote
Yesterday
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:31p, 1/31/08
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:31p, 1/31/08
quote:
It would have the flying qualities of an F-4 with both engines out????/


What if it fired its missles backwards?
Reply Quote
Texaggie7nine
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:36p, 1/31/08
quote:
If you can't understand that the speed of the conveyor belt has no real effect on the plane's ability to move forward then I don't know what can be done to convince you


When the F did I ever say that it did? I am saying that by the wording of the statement the plane is stationary if it is going the same speed away from the belt movement as the belt is traveling.

Reply Quote
Red Skye
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:38p, 1/31/08
AG
No, it's not.
Reply Quote
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:38p, 1/31/08
the wheels may be going the speed of the conveyor, but the plane moves forward, the conveyor goes faster, the wheels go faster, the plane moves forward....ad infinatum, then the plane takes off
Reply Quote
coconutED
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:41p, 1/31/08
AG
quote:
I am saying that by the wording of the statement the plane is stationary if it is going the same speed away from the belt movement as the belt is traveling.


And we are saying that this is impossible. It can never happen. Not in theory. Not in practice. NEVER!

Imposing such a condition on the problem makes it unsolvable. In engineering, we refer to this as over specifying your initial conditions.
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:46p, 1/31/08
AG
quote:
What if it fired its missles backwards?


If the missiles had a coconut on a string between them then it's possible...
Reply Quote
OneManArmy
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:46p, 1/31/08
By giving the belt a speed you are giving a speed relative to a stationary point (the ground). For the problem to make sense one would naturally assume that the plane's speed is also relative to the ground because that is the assumed point of reference for everything.

Now....

Reply Quote
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
8:48p, 1/31/08
quote:
then it's possible
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
9:04p, 1/31/08
AG
ONLY with the coconut on a string, mind you...
Reply Quote
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
9:06p, 1/31/08
quote:
then it's possible


what if the block of wood airplane was glued to the conveyor, and fired its missiles backwards?

[This message has been edited by fahraint (edited 1/31/2008 9:20p).]
Reply Quote
Rex Racer
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
9:26p, 1/31/08
AG
This thread reminds me of a discussion that I once had with howdydamnit04.

http://www.texags.com/main/forum.reply.asp?forum_id=12&topic_id=507647
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
9:44p, 1/31/08
AG
quote:
what if the block of wood airplane was glued to the conveyor, and fired its missiles backwards?


As long as the missiles had the coconut on the string, it would take off...

If it was glued down, it would just take that damn conveyor for a ride...it needed to get out anyways....
Reply Quote
fahraint
User Profile Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
9:47p, 1/31/08
what if the coconut had no milk inside, because it was previously drained on Survivor?
Reply Quote
Ag with kids
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
10:16p, 1/31/08
AG
Then drop the conveyor down on that Survivor choad because he ruined the experiment!!!!
Reply Quote
Texaggie7nine
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
11:03p, 1/31/08
quote:
And we are saying that this is impossible. It can never happen. Not in theory. Not in practice. NEVER!


I already explained earlier how it could be accomplished in practice for a moment. You just have a problem dealing with the theoretical. You can't say, well it's impossible so we will say the wording of the myth can mean only one thing.



Reply Quote
Texaggie7nine
User Profile
Private Message
Ignore User Stop Ignoring
How long do you want to ignore this user?
24 hours One week Permanently Cancel
11:06p, 1/31/08
quote:
that the plane's speed is also relative to the ground because that is the assumed point of reference for everything.


That's pointless, because then, if the plane is going 25 mph forward, relative to the ground, then it is going 25 mph relative to the ground and it takes off. So why even pose the question of the myth.

Basically the myth should be cut off at "the plane is moving forward at takeoff speed, relative to the ground" and that would be end of story. You can say anything after that but it would not negate that you stated that the plane is going at takeoff speed relative to the ground.

Reply Quote
 
×
subscribe Verify your student status
See Subscription Benefits
Trial only available to users who have never subscribed or participated in a previous trial.