"calculate the speed of this sound wave by recording how much time it takes to travel 5 meters. use the (old school) velocity equation: v = d/t show units in your work. 292.39 m/s= 5 meters/.0171 secs." and here's the question i need with: "based on the speed you measured above, how long would it take for you to hear thunder if you observed lightning and it was seen to be 1620 meters away? "

1) sound velocity reported by you : 292.39 m /s

2) time to travel 1620m at that velocity: t = d / v = 1620 m / 292.39 m/s = 5.54 s, since the moment the sound wave started.

3) You might wanted to tell the time since you watched the lightning.

Then you can calculate the time since the lighting was generated,1620 m away from you, until you saw it, using the speed of light:

 speed of light = 3*10^8 m/s => t = 1620 m / (3*10^8m/s) =0.0000054 s

Then, this time is completely neglectible, and yet the answer is 5.54 s, as calculated in the step 2.

All are great precautions but you can still lift lighter and different muscles in between hard workdays. this keeps other muscles not usually used in shape.