World Science Scholars
8.1 Calculating the Time Difference
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video


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Shauray Kakade
mind blown
Shakti Kashyap
I'm feeling so thankful, that I'm getting to learn and understand things directly from Physicist Brian Greene. I saw you firstly on Discovery Channel and search about you on internet and Wikipedia. You along with your fellow Physicist like Brian Cox , Lawrence M. Krauss , Michio Kaku ,etc , you all are great personalities and the most important person on Earth since all of you are pro in Physics (the fundamental subject) you are always an idol to me , you are so Inspiring , and now I'm getting lectures from you, Omg its a dream Come true . Thank you so much sir for starting this program to reach everyone across the globe and giving us chance to directly learn things from you.. I can't elaborate in words how blessed I'm feeling..🥲🥰 i want to become a Physicist too , to find the Ultimate truth and meaning but , due to lack of teacher here at my place, where people rarely go Deep into Concepts, i always wish i have a teacher who can teach what Scientist really mean to say when giving their laws.. and Now i found Your Videos.. Thank you so much sir❤️, Take Care Sir..
Roelof Vuurboom
We can get a feel for the numbers without having to use a calculator. Say v is just 1 meter less than the speed of light so = c-1 (or 299792457 m/s). Here c is in m/s. The formula Lv / (c^2 - v^2) becomes L(c-1) / (c^2 - (c-1)^2) = L(c-1)/ (2c-1) = L/(2 + 1/(c-1) ). 1/(c-1) is very small so the time difference is very close to L/2. For a 10000m train this is very close to 5000 seconds which is about 83 minutes. The video states that this value (83 minutes) is gotten with 299792457.999999999 m/s. This is wrong. The calculation in the video was using c-1 or 299792457 m/s which is 99.999986% of the speed of light.
Roelof Vuurboom
And if the carriage is just 10m long then the time difference is 5s.
Sachin Saurav
At 3:47 . CTb = L/2 + VTb . The time in CTb refers to the total time light took to reach PofForward . And CTb represents Total Distance light took. L/2 refers to the actual distance from candle to PofForward . But As the Distance increases due to moving train . Say it moved M feets away from the moment light was emmited . And when light reached PofForward, PofForward is now M feets away from the point where light only had to travel L/2 to reach PofForward (if train is at rest) . So why light took Tb amount of time to cover that extra distance.? Isn't Tb is meant to represent the total amount of time light took to reach PofForward ? If CTb and VTb are different , why amount of time (Tb) is same ?
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