Question

Fireworks! Explosions! Bang!

The video below shows a series of fireworks explosions, but was recorded in slow motion at 240 frames per second. You can see the audio sound track pictured at the bottom of the video.

1. Here is some data from a nearby weather station on the night of the fireworks. The video was recorded at about 10:30 PM.

Look at the data and calculate the speed of sound at the time of recording.

  

2.There are four explosions. Select one of them to find the distance of explosion. In the space below, describe how you determined the distance from the explosion to the camera. Show your calculation clearly.

the first explosion is chosen.

light shown @ .175 s.

sound @ .662 s.

3.Will the time between the flash and the bang shorter or longer if it were a much colder night and the explosion had occurred at the same distance? Explain.

Answer 1

1) towe know that, velate on rounde avait, where to tampreture at kelvers scale. the tempréture of that night was 25.C So, 250 25+273) = 298 298k (= T27. let). We know that relocity of round at ooc tempneture (23 €) = 273k (=To let) temprature el ngt u=331.3 mln. Ld at Ta terpretura, vebaly of sound in we have skut. [ka proportionality constant - a diq have Dung ny we & Tz V kiti T2 va ~ = 331.34 273 - 36. 131 - 346. 16 mb

So, the velocity of sound d that we wight. hva= 3614 als rebaty of light a e=3x108 als (2) Let the distance between the observer and the exp plosen en S Wee toon that, petely owned diss velocity assed destence & time. teave Velocity cronot distance & time We know that Grossed distance velocity on to me a crossed distance (5) velocity . & Time taken by light to croon the distance est, [tia 0.175 re - Time teken by round to cross the distance, its de (ta= 0. 662 sec tart,= (0.662 -0.178) WS V2 20.987 ve 2 S o = 0-287 ch a

2 0.287 11 0287 V 2 ट 346-14 arra) - (3x1080 is 168.97 - Tituen required distance of an explosion (3) Now, the rebcety of light does not depends on temprature So e=const. So, time taken by son light on (- do) es constant Now the velocity of sound in We at sempretul Ta tempreture fron , say that at lowen temprature the veoats of sound in ters. As time taken by sound is, tp tao s with decreasing us to le crearer. N. Sot so as at low temprature it, i fixed and to encreases, eo their time gap (ta-ti) abs to increase
The answers are in the images. Page number is mentioned at right top. Here the temperature of that is not mentioned. So by general convention, I consider the tempreture is 25° C. If you want any other tempreture, then just replace the value of T₁ at the calculation at part 1.