posted by musuma .
A physics student drops a physics text book into a mine shaft 250m deep,where the average mine temperature is 5degrees celsius.Show that the sound of the book striking the bottom is heard after 7.82seconds
d = Vo*t + 4.9*t^2 = 250 m.
0 + 4.9t^2 = 250.
t^2 = 250 / 4.9 = 51.0.
Tf = 7.14 s. = Fall time.
d = V*T.
T = d/V = 250m / 343m/s = 0.729 s. =
Time for sound to travel 250 meters up.
Tf + T = 7.14 + 0.729 = 7.87 s.