Answer:
The whales experience pressures of about 9.87Mpa at this depth of 1km into the water.
Step-by-step explanation:
The absolute pressure can be calculated using the formula: P Abs = P Guage + P Fluid.
This means that once the whales dive under the water, both the pressure from the atmosphere and the pressure from the water is acting on them.
The Guage pressure is 101325 Pa. This can be obtained from standard tables.
The fluid pressure at a depth of 1km (1000 m) can be obtained using the formula:

Where
= density of water = 997 kg/m³
g = acceleration due to gravity = 9.8 m/s2
h = depth of dive = 1000m

Therefore, Absolute pressure = 101325 Pa + 9770600 Pa = 9871925 Pa
The whales experience pressures of about 9.87Mpa at this depth of 1km