« previous next »
Pages: [1] 2   Go Down

Author Topic: Tire Speed!  (Read 1327 times)

Offline earl1937

  • Gold Member
  • *****
  • Posts: 2290
Tire Speed!
« on: May 07, 2013, 06:10:05 PM »
 :airplane: I am rolling out after landing in my B-17 and I am doing 20MPH, what is the speed of the part of the tire which is touching the ground doing in MPH?
Logged
Blue Skies and wind at my back and wish that for all!!!

Offline Arlo

  • Radioactive Member
  • *******
  • Posts: 24759
Re: Tire Speed!
« Reply #1 on: May 07, 2013, 06:30:53 PM »
I think I've seen a version of this online already:

http://www.youtube.com/watch?feature=player_embedded&v=Qhm7-LEBznk    :D

(Ducks)  :bolt:
Logged

Offline Karnak

  • Radioactive Member
  • *******
  • Posts: 23047
Re: Tire Speed!
« Reply #2 on: May 07, 2013, 06:33:11 PM »
Quote from: earl1937 on May 07, 2013, 06:10:05 PM
:airplane: I am rolling out after landing in my B-17 and I am doing 20MPH, what is the speed of the part of the tire which is touching the ground doing in MPH?
0mph.

If you stand on the brakes it will be doing 20mph, briefly.
Logged
Petals floating by,
      Drift through my woman's hand,
             As she remembers me-

Offline RTHolmes

  • Plutonium Member
  • *******
  • Posts: 8260
Re: Tire Speed!
« Reply #3 on: May 07, 2013, 06:34:58 PM »
relative to what? </Einstein>
Logged
71 (Eagle) Squadron

What most of us want to do is simply shoot stuff and look good doing it - Chilli

Offline colmbo

  • Gold Member
  • *****
  • Posts: 2246
      • Photos
Re: Tire Speed!
« Reply #4 on: May 07, 2013, 07:02:32 PM »
Quote from: earl1937 on May 07, 2013, 06:10:05 PM
:airplane: I am rolling out after landing in my B-17 and I am doing 20MPH, what is the speed of the part of the tire which is touching the ground doing in MPH?

Indicated, calibrated, true or ground?
Logged
Columbo

"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

Fate whispers to the warrior "You cannot withstand the storm" and the warrior whispers back "I AM THE STORM"

Offline Arlo

  • Radioactive Member
  • *******
  • Posts: 24759
Re: Tire Speed!
« Reply #5 on: May 07, 2013, 07:14:29 PM »
Skidding or rolling?
Logged

Offline mechanic

  • Plutonium Member
  • *******
  • Posts: 11308
Re: Tire Speed!
« Reply #6 on: May 07, 2013, 07:43:14 PM »
Two answers, the obvious one is 0mph. Although that is ambiguous because the part that is touching the tarmac is always changing.

The other obvious answer is 20mph, because the aircraft is moving at 20mph along with everything attached to it.

I'm guesing this is some kind of clever riddle and I am wrong twice.
Logged
And I don't know much, but I do know this. With a golden heart comes a rebel fist.

Offline Tank-Ace

  • Persona Non Grata
  • Platinum Member
  • ******
  • Posts: 5298
Re: Tire Speed!
« Reply #7 on: May 07, 2013, 08:15:38 PM »
You could also probably find an equation for the speed of any given point on the tire as it rolls along the ground, based on the radius...
Logged
Quote from: Arlo on April 28, 2014, 06:25:38 PM
You started this thread and it was obviously about your want and desire in spite of your use of 'we' and Google.

"Once more unto the breach"

Offline BaldEagl

  • Plutonium Member
  • *******
  • Posts: 10791
Re: Tire Speed!
« Reply #8 on: May 07, 2013, 10:20:53 PM »
Quote from: mechanic on May 07, 2013, 07:43:14 PM
The other obvious answer is 20mph, because the aircraft is moving at 20mph along with everything attached to it.

Actually that speed would oscillate based on whether the particular part of the tire was moving forward over the top (faster than 20 mph) or rearward under the bottom (slower than 20 mph) equalizing at 20 mph in the horizontal plane.

If the question had been about a particular and constant point on the tire it would be much faster than 20 mph but we'd need the tire radius or diameter to calculate the speed.  As that information wasn't provided we can eliminate that answer.

The real answer is 0 mph for the portion of the tire in contact with the ground which was the question.
Logged
I edit a lot of my posts.  Get used to it.

Offline earl1937

  • Gold Member
  • *****
  • Posts: 2290
Re: Tire Speed!
« Reply #9 on: May 08, 2013, 04:16:58 PM »
Quote from: BaldEagl on May 07, 2013, 10:20:53 PM
Actually that speed would oscillate based on whether the particular part of the tire was moving forward over the top (faster than 20 mph) or rearward under the bottom (slower than 20 mph) equalizing at 20 mph in the horizontal plane.

If the question had been about a particular and constant point on the tire it would be much faster than 20 mph but we'd need the tire radius or diameter to calculate the speed.  As that information wasn't provided we can eliminate that answer.

The real answer is 0 mph for the portion of the tire in contact with the ground which was the question.
:banana: :banana: :banana: You sir, are correct, the part touching pavement is NOT moving! If it moved, it would be skidding or slipping! LOL
Logged
Blue Skies and wind at my back and wish that for all!!!

Offline mtnman

  • Gold Member
  • *****
  • Posts: 2438
Re: Tire Speed!
« Reply #10 on: May 08, 2013, 08:10:12 PM »
Quote from: earl1937 on May 08, 2013, 04:16:58 PM
:banana: :banana: :banana: You sir, are correct, the part touching pavement is NOT moving! If it moved, it would be skidding or slipping! LOL

Is this with, against, or somewhat across the rotation of the earth?  That would have an effect on the speed of the part touching the ground, no?
Logged
MtnMan

"Those who hammer their guns into plows will plow for those who do not". Thomas Jefferson

Offline BaldEagl

  • Plutonium Member
  • *******
  • Posts: 10791
Re: Tire Speed!
« Reply #11 on: May 08, 2013, 11:07:43 PM »
Quote from: earl1937 on May 08, 2013, 04:16:58 PM
:banana: :banana: :banana: You sir, are correct, the part touching pavement is NOT moving! If it moved, it would be skidding or slipping! LOL

Thank you for the accolades (if that's what dancing bananas are... which reminded me of this: http://www.allmedia.com.au/bananana/) but Karnak got it first.
« Last Edit: May 08, 2013, 11:12:38 PM by BaldEagl »
Logged
I edit a lot of my posts.  Get used to it.

Offline Motherland

  • Plutonium Member
  • *******
  • Posts: 8110
Re: Tire Speed!
« Reply #12 on: May 12, 2013, 05:26:50 PM »
see: physics I lecture 10 or so
Logged

Offline Arlo

  • Radioactive Member
  • *******
  • Posts: 24759
Re: Tire Speed!
« Reply #13 on: May 12, 2013, 05:35:12 PM »
How fast are my spinner hubcaps moving when my tires are stationary on the rearm pad.  :D
Logged

Offline Bino

  • Platinum Member
  • ******
  • Posts: 5937
Re: Tire Speed!
« Reply #14 on: May 15, 2013, 10:23:58 AM »
Quote from: earl1937 on May 07, 2013, 06:10:05 PM
:airplane: I am rolling out after landing in my B-17 and I am doing 20MPH, what is the speed of the part of the tire which is touching the ground doing in MPH?

African or European?
Logged


"The plural of 'anecdote' is not 'data'." - Randy Pausch

PC Specs
Pages: [1] 2   Go Up
« previous next »