Chapter 19, Problem 3A

a. By how much does the water pressure on a submarine change when the submarine dives to double its previous depth (neglect the very real effect of atmospheric pressure above)?

b. If the submarine operated in fresh water, would the pressure it feels be greater or less than at the same depth in salt water?

To determine

To explain: The change in the water pressure on the submarine for the given changes.

Explanation of Solution

Introduction:

The pressure of liquid which was at rest depends on three things, density, gravity and depth. Liquid pressure was directly proportional to depth of liquid.

For any given liquid the liquid pressure increases as we go deeper in liquid. As submarine went deep in the sea the pressure of liquid increases due to increase in depth.

Conclusion:

As submarine dived double of its previous depth the liquid pressure on the submarine also get doubled.

To determine

To explain: Whether the pressure felt by submarine in fresh water is greater or less than at same depth in salt water.

Explanation of Solution

Introduction:

The pressure of liquid which was at rest depends on three things, density, gravity and depth. Liquid pressure was directly proportional to depth of liquid.

Density of fresh water was less than salt water. Salt water contains particles of salt which exerts a pressure on submarine. So when submarine in fresh water it feel less liquid pressure at same depth in salt water.

Conclusion:

A less pressure is felt by a submarine in a fresh water than in salt water for same depth.