The pilot of an airplane traveling 180km/h wants to drop supplies to flood victims isolated on a patch of land 160 m below. the supplies should be dropped how many seconds before the plane is directly overhead?

Adolphin emits ultrasound at 100khz and uses the timing of reflections to determine the position of objects in the water. part a what is the wavelength of this ultrasound? assume that temperature of water is 20 degrees c. answer in cm