Reaktiivjõud

Reaktiivjõud, also known as reactive force, is a fundamental concept in physics, particularly in the study of forces and motion. It is most famously described by Isaac Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. This means that whenever an object exerts a force on another object, the second object exerts a force of equal magnitude and opposite direction back on the first.

This principle is not limited to simple interactions between solid objects. Reaktiivjõud is also evident in phenomena involving fluids and gases. For example, when a rocket expels hot gases downwards, the expulsion of these gases (the action) creates an upward force on the rocket (the reaction), propelling it into space. Similarly, a swimmer pushes water backward (action), and the water pushes the swimmer forward (reaction), allowing them to move through the water.

Understanding reaktiivjõud is crucial for analyzing the motion of everything from a person walking to the complex dynamics of planetary orbits. It is a ubiquitous force that shapes our physical world and is a cornerstone of classical mechanics. The concept highlights the interconnectedness of forces in the universe, where no force exists in isolation.