A water balloon is dropped from a cliff. Exactly 3 sec later, the sound of the balloon hitting the ground reaches the top of the cliff. How high is the cliff? (Thanks in advance for any help you can provide!)

2 answers

height = -4.9t^2
when t = 3
height = 4.9(9) m = appr 44.1 m
If you want to include the travel time of the sound, you have to look up the speed of sound in air. Let's say that is 343.2 m/s. So now, if the falling time is t, then we have

4.9t^2 = 343.2(3-t)
t = 2.88

So, the balloon fell for only 2.88 seconds, making the distance

4.9*2.88^2 = 40.64 m