Finding Temperature with Speed?

  • Context: Undergrad 
  • Thread starter Thread starter alucrid
  • Start date Start date
  • Tags Tags
    Speed Temperature
Click For Summary

Discussion Overview

The discussion revolves around the relationship between the speed of a soccer ball and the temperature required for it to ignite, specifically exploring how to calculate the necessary speed to reach ignition temperature through various equations and principles. The scope includes theoretical reasoning and mathematical modeling.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks to prove that a soccer ball cannot catch fire by determining the speed needed to reach the ignition temperature of leather, which is 212 degrees Celsius.
  • Another participant questions the assumption of a one-to-one relationship between temperature and speed, pointing out that heating a soccer ball does not cause it to move.
  • A participant clarifies that they are looking for an equation that relates speed and temperature, indicating they can find other necessary variables like mass.
  • One participant mentions that supersonic aircraft experience significant heating at high speeds, suggesting that catching fire may require speeds around 2000 mph, but notes the complexity of the relationship due to factors like frictional heating and wave drag.
  • Another participant proposes a method to approach the problem, suggesting calculations involving viscous drag and the specific heat of the football material to estimate temperature rise.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between speed and temperature, with no consensus on a straightforward equation or method to determine the necessary speed for ignition. The discussion remains unresolved regarding the best approach to the problem.

Contextual Notes

Participants acknowledge the complexity of the problem, noting that there is no simple equation and that various factors such as drag and material properties must be considered. The discussion highlights the need for assumptions and specific conditions in calculations.

alucrid
Messages
4
Reaction score
0
I'm trying to prove that a soccer ball cannot catch on fire. I'm trying to prove that by determining how fast a ball needs to go to reach that temperature, then comparing it with the fastest kick and its temperature. Right now I know that leather ignites at 212 degrees Celsius and that the fastest kick was measured at 221 km/h. How exactly would I determine the speed of an object with the temperature and vice versa. An equation should be all I need, I've tried looking for one but to no avail. Thanks.
 
Science news on Phys.org
alucrid said:
How exactly would I determine the speed of an object with the temperature and vice versa. An equation should be all I need, I've tried looking for one but to no avail.

Why do you think there is a one-to-one relationship between temperature and speed? If you heat a soccer ball, it doesn't start moving.
 
Vanadium 50 said:
Why do you think there is a one-to-one relationship between temperature and speed? If you heat a soccer ball, it doesn't start moving.

Oh, I wasn't thinking that. I was just saying an equation that had both speed and temperature in it so I can solve for the missing variable. If it includes other information I could easily find that out, i.e. mass of a soccer ball, etc. So with the temperature I could solve for the speed and with the speed I could solve for the temperature.
 
Supersonic aircraft start getting noticeably hot at about 1500 mph. Actually catching fire might require 2000mph or so. But there is no simple equation for this. It's a matter of frictional heating and wave drag. http://en.wikipedia.org/wiki/Wave_drag
 
Last edited:
On a very high level you would need a few things. But as others said - there is no "easy" equaton. And I doubt you will get a good answer because the velocity might require an extremely powerful kick that may deform the fotball for good. However academically thinking I would approach the problem like this:

1. Calculate the viscous drag by the air on the football. Calculate the work done by the foot ball to overcome this drag (force x distance). Assume a straight path with uniform velocity or a projectile motion depending on how simple or how realistic treatment you are looking for.

2. Use the specific heat of the football material to calculate the temperature rise. And bingo this equation is what you may be looking for.

-SNB
 

Similar threads

  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 35 ·
2
Replies
35
Views
2K
  • · Replies 24 ·
Replies
24
Views
4K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 12 ·
Replies
12
Views
10K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K