when lightning strikes you can see it at a speed of 3x10^8m/s. But you hear thunder at about 340m/s in 70 degrees air temperature. a) If you are a mile away from lightning, how long of a delay is there?

Question

when lightning strikes you can see it at a  speed of 3x10^8m/s. But you hear thunder at about 340m/s in 70 degrees air temperature. a) If you are a mile away from lightning, how long of a delay is there?
b) if the delay between the lightning and thunder were 1s how far away would you be in km and in miles?

a) I used d=d_0+v_0t+1/2at^2
which becomes d=v_0t
1609.34=340t
t=4.73s
b) d=v_0t
d=3x10^8 m/s(1s)
d=3x10^8m
=18641.14mi
=300,000 km

But this doesn't make any sense. Did i do something wrong?

DrBob222 · Answer

In part b you used the speed of light for Vo but its the speed of sound that determines how long it takes to hear it.