A sound wave is incident on a pool of fresh water (25 °C). The sound enters the water perpendicularly and travels a distance of 0.45 m before striking a 0.15-m-thick copper block lying on the bottom. The sound passes
through the block, reflects from the bottom surface of the block, and returns to the top of the water along the
same path. How much time elapses between when the sound enters and when it leaves the water?