The formula M=1/5t can

Question

The formula M=1/5t can be used to determine how far M, in miles, you are from lightning when it's thunder takes t seconds to reach your ears. If it takes 4 sec for the sound of thunder to reach you after you have seen the lightning, how far is the storm away from you?

Answer 1

Dejah,

 

Your cited formula is wrong for two reasons:

 

1.  Its dimensions make no sense, and they should in every valid formula.

     M = 1/(5t)

    miles =? 1/seconds.  No way!

 

2.  I t makes no sense from a Physics standpoint.  The larger t is, the longer it takes the sound to reach you, the bigger the distance should be, but this formula makes the distance shrink.

 

e.g,  t = 4 sec  ,  M= 1/(5)(4) = 1/20

        t = 100 sec, M = 1/(5)(100) = 1/500  and that would be 10 feet away ??  Ridiculous!

 

So check out your formula and apply these two tests I cited.

Answer 2

You have your formula that consists of 2 variables.  One variable is known, t, so plug in t into that formula to obtain M.