NAPT - Navy Advanced Programs Thermodynamics and Heat Transfer Questions and Answers

Question 1

Aboard a naval vessel, a sealed, rigid container filled with an ideal gas is moved from a cool storage room at 10°C to the deck where the temperature is 30°C.
If the initial pressure was 150 kPa, what is the final pressure inside the container, assuming the volume remains constant?

Accepted Answer

160 kPa

Answer

140 kPa

Answer

150 kPa

Answer

450 kPa

Question 2

Which of the following scenarios best exemplifies heat transfer primarily through convection?

Accepted Answer

A ventilation system circulates cooled air throughout a ship's compartment.

Answer

The handle of a metal wrench left in the sun becomes hot.

Answer

A sailor feels the warmth of a nearby steam pipe without touching it.

Answer

The hull of a ship gets warm where it is in direct contact with a hot pier.

Question 3

The First Law of Thermodynamics is a statement of the conservation of energy. For a closed system, it is expressed as ΔU = Q - W. In this equation, what does ΔU represent?

Accepted Answer

The change in the internal energy of the system.

Answer

The work done by the system.

Answer

The heat added to the system.

Answer

The total entropy of the system.

Question 4

A 2 kg block of aluminum (specific heat capacity ≈ 900 J/kg°C) is used as a heat sink for an electronic component. If the component transfers 18,000 Joules of heat to the block, what is the temperature increase of the aluminum block?

Accepted Answer

10°C

Answer

5°C

Answer

20°C

Answer

9,000°C

Question 5

In the design of a ship's hull insulation, materials with low thermal conductivity are chosen. What is the primary mode of heat transfer that these materials are designed to minimize?

Accepted Answer

Conduction

Answer

Convection

Answer

Radiation

Answer

Advection

Question 6

A heat engine, such as a ship's propulsion plant, operates by taking in heat (Q_H) from a high-temperature source, converting some of it into useful work (W), and rejecting the remaining heat (Q_C) to a low-temperature sink. Which of the following statements correctly describes the relationship between these quantities according to the First Law of Thermodynamics?

Accepted Answer

W = Q_H - Q_C

Answer

W = Q_H + Q_C

Answer

Q_H = W - Q_C

Answer

Q_C = W + Q_H

Aboard a naval vessel, a sealed, rigid container filled with an ideal gas is moved from a cool storage room at 10°C to the deck where the temperature is 30°C.If the initial pressure was 150 kPa, what is the final pressure inside the container, assuming the volume remains constant?

Aboard a naval vessel, a sealed, rigid container filled with an ideal gas is moved from a cool storage room at 10°C to the deck where the temperature is 30°C.
If the initial pressure was 150 kPa, what is the final pressure inside the container, assuming the volume remains constant?