Am I being punked? (Physics problem)

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In summary, the conversation discussed estimating the speed of sound using a rule of thumb that every 5 seconds between a lightning flash and the following thunder gives the distance of the storm in miles. The answer was 300 m/s. The actual speed of sound is a function of temperature and pressure, but for estimation purposes, 331 m/s can be used. It was also mentioned that a "metric mile" is equivalent to 1500 meters, and using this information, the speed of sound can be estimated at about 300 m/s based on the given rule of thumb.
  • #1
Tatum
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This was problem 7 in the homework from the 2nd chapter(Kinematics in one dimension) of my physics book:

According to a rule of thumb, every five seconds between a lightning flash and the following thunder gives the distance of the storm in miles. Assuming the flash of light arrives in essentially no time at all, estimate the speed of sound in m/s from this rule.

The answer was 300 m/s. I figure I would need speed of light and sound but the speed of sound isn't anywhere in this book. Wouldn't I need to know how many miles would equal 5 seconds? I need help, thanks
 
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  • #2
arent they saying that it takes 5 seconds per mile for the sound to get there? how they said every five seconds between them gives the distance in miles... so that would be like saying every 5 seconds is one mile... i think
 
  • #3
If a mile is 5280 feet and sound takes 5 seconds to travel that far then it travels about 1000 feet per second. The speed of light is about 186,000 miles per second so for all intents it is instantaneous.

The actual speed of sound is a function of temperature and pressure (altitude) but it doesn't change all that much. To understand a concept a first order answer is more than adequate.

Pay attention in your physics class as it is the study of the physical world and will be of value to you all your life. That is more than I can say of many classes.

Good luck
Kirk
 
  • #4
Speed of sound

If you're not given an air temperature, you can just use 331 m/sec as the speed of sound.
 
  • #5
The speed of sound was supposed to be estimated. THis means you do not need the speed of sound to begin with.

Every track star knows that the "metric mile" is 1500 meters. (This is actually .92 miles, but it's close). If 1500 meters in 5 seconds, then how fast?
 
  • #6
300 m/s

So for the problem, every 5 seconds is 1 mile. 1 mile = 1.61 km = 1610 meters. That's 322 meters per second which is about 300 m/s. Whoa DUDES! Thanks a lot, I'm on the road to my noble prize!
 
  • #7
Tatum said:
300 m/s

So for the problem, every 5 seconds is 1 mile. 1 mile = 1.61 km = 1610 meters. That's 322 meters per second which is about 300 m/s. Whoa DUDES! Thanks a lot, I'm on the road to my noble prize!

You mean Nobel Prize? :tongue2:
 

1. What does "being punked" mean in a physics problem?

In a physics problem, "being punked" refers to the possibility that the problem is designed to trick or deceive the reader into making a mistake. This can happen when the problem includes misleading information or requires the reader to make assumptions that are not explicitly stated.

2. How can I tell if I am being punked in a physics problem?

One of the best ways to tell if you are being punked in a physics problem is to carefully read and analyze the given information. Look for any inconsistencies or contradictions that may indicate the problem is trying to trick you. You can also try solving the problem using different methods or approaches to see if you get the same result.

3. Is being punked a common occurrence in physics problems?

No, being punked is not a common occurrence in physics problems. Most physics problems are designed to test your understanding of key concepts and principles, rather than to deceive you. However, it is still important to be aware of the possibility of being punked and to approach every problem with caution and critical thinking.

4. What should I do if I think I am being punked in a physics problem?

If you suspect that you are being punked in a physics problem, the first thing you should do is stop and carefully re-read the problem. Make sure you understand all of the given information and try to identify any potential tricks or traps. If you are still unsure, you can consult with a teacher or classmate for their input.

5. Are there any strategies for avoiding being punked in a physics problem?

Yes, there are some strategies that can help you avoid falling for tricks or traps in a physics problem. These include carefully reading and analyzing all of the given information, using multiple methods to solve the problem, and checking your work for errors. It is also helpful to have a strong understanding of key physics concepts and principles, as this can help you identify any inconsistencies or incorrect information in the problem.

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