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1) You and your friend Callie are hiking in the Black Hills near Rapid City, Sou

ID: 2255873 • Letter: 1

Question

1) You and your friend Callie are hiking in the Black Hills near Rapid City, South

Dakota, when you stumble upon a ghost town. As you walk around, you nd a well

in the center of the town. The well has no pulley or rope. You look down into the

well and from how dark it is you can tell that it is deep. Callie knows that you took

some physics so she asks you to gure out the depth of the well. You take a stone

and drop it into the well and you and Callie wait for the splash. Callie measures the

time with her digital watch and tells you that it took 4 seconds. How deep is the well?


Explanation / Answer

Let d be the depth of the well



Also let Speed of Sound be 340 m/sec



Therfore



As we know



S = ut + 0.5*a*t^2



Therefore



d = 0 + 0.5*9.8*t^2



t = sqrt(d/4.9)



Therefore



Total Time = sqrt(d/4.9) + d/340



sqrt(d/4.9) + d/340 = 4



d = 70.48 m