The focus on this question is sound. If I were in my pool and I observe a lightn

Question

The focus on this question is sound. If I were in my pool and I observe a lightning bolt, followed by the sound of thunder three seconds later. How close is that lightning determined to be to my location. Please show the physics (math) and explanation for the solution.

Expert Answer manish27

Let the distance for sound and linghting is d meter from the pool.

and speed of sound in air is 343.2 m/s and speed of light in air is 3 imes108 m/s

we have time t= Distance / Speed so rac{d}{343.2}-rac{d}{3 imes 10^{8}}=3

(As the difference of lightining and sound is 3 second)

dleft ( rac{1}{343.2}-rac{1}{3 imes 10^{8}} ight )=3 d imes0.0029=3

d=3 / (0.0029) d=1034.48 m ANS

Question is where did the (0.0029 come from? What are some mistakes to avoid when dealing with this type of question?

Explanation / Answer

Let say the distance covered by the lighting is d and it covers it in t seconds
By the sound same distance is covered in (t+3) seconds
Now the
distance = speed*time
for sound speed = 343.2 m/s
and for light = 3*108 m/s
Now
3*108*t = 343.2*(t+3)
On solving we get t = 3.432*10-6 s
Now the distance = 3*108*3.432*10-6 = 1029.6 m

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects