a rock is dropped from rest into a well. (a) the sound of the splash is heard 2.40 s after the rock is released from rest. how far below the top of the well is the surface of the water? the speed of sound in air (at the ambient temperature) is 336 m/s. (b) what if? if the travel time for the sound is ignored, what percentage error is introduced when the depth of the well is calculated?