Cadet Competition Written Practice Exam

According to Newton's Second Law of Motion, the force applied to a rocket is the _____ created by the controlled explosion in its engines.

1. heat

2. thrust

3. pressure

4. weight

The correct answer is: pressure

The correct answer is thrust. In the context of rocketry and Newton's Second Law of Motion, thrust refers specifically to the force generated by the engines during the controlled explosion of propellant. This force propels the rocket upward, overcoming gravity and other forces. Thrust is the reaction force that results from the expulsion of exhaust gases at high speed, aligning with Newton's third law, which states that for every action, there is an equal and opposite reaction. When propellant is combusted, it rapidly expands and is expelled out of the rocket's nozzle, resulting in thrust that pushes the rocket in the opposite direction. While heat, pressure, and weight are important concepts in physics and engineering, they do not accurately describe the force that propels a rocket in the context of this question. Heat refers to thermal energy, pressure relates to the force exerted per unit area, and weight is the gravitational force acting on an object. None of these terms encapsulate the specific mechanism of propulsion provided by the rocket's engines.