Finding Temperature with Speed?

In summary, the individual is trying to prove that a soccer ball cannot catch on fire by determining the speed it needs to reach a certain temperature and comparing it to the fastest kick which was measured at 221 km/h. They are looking for an equation to solve for the missing variable of speed or temperature. However, it is not a straightforward calculation and would require considering factors such as frictional heating and wave drag. There is no simple equation for this and it may be difficult to get a precise answer due to the potential deformation of the ball from a powerful kick. The suggested approach would involve calculating the viscous drag and work done by the ball, as well as using the specific heat of the ball's material to determine the temperature increase.
  • #1
alucrid
4
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.
 
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  • #2
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.
 
  • #3
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.
 
  • #4
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
 
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  • #5
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
 

1. How does speed affect temperature?

As an object moves faster, its molecules vibrate more rapidly, which increases their energy and raises the object's temperature. This is because kinetic energy, or the energy of motion, is converted into thermal energy.

2. Can speed be used to accurately measure temperature?

Yes, speed can be used to measure temperature through the use of a thermometer. The faster the molecules are moving, the higher the temperature will be on the thermometer.

3. What is the relationship between speed and temperature in gases?

The relationship between speed and temperature in gases is known as the Kinetic Theory of Gases. This theory states that the average kinetic energy of gas molecules is directly proportional to the temperature of the gas. In other words, as temperature increases, so does the speed of gas molecules.

4. How does the speed of molecules affect the temperature of a substance?

The speed of molecules directly affects the temperature of a substance. When molecules move faster, they collide more frequently, resulting in an increase in temperature. Conversely, when molecules move slower, they collide less frequently, resulting in a decrease in temperature.

5. Can temperature be calculated using speed alone?

No, temperature cannot be accurately calculated using speed alone. Other factors, such as the type of substance and its specific heat capacity, must also be taken into consideration when calculating temperature. However, speed can be used as an indicator of temperature in certain situations, such as with a thermometer.

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