Reaktsioonijõud

Reaktsioonijõud is a fundamental concept in physics, often discussed in the context of Newton's third law of motion. This law states that for every action, there is an equal and opposite reaction. The reaction force is the force that opposes the action force. When one object exerts a force on a second object, the second object simultaneously exerts a force back on the first object. These two forces are always equal in magnitude and opposite in direction.

A common example is pushing a wall. When you push the wall, you are exerting an action force. The wall, in turn, exerts an equal and opposite reaction force back on you. This reaction force is what prevents you from passing through the wall. Similarly, when a rocket expels fuel downwards, the action force is the expulsion of the fuel. The reaction force is the upward thrust that propels the rocket into space. It is important to note that the action and reaction forces act on different objects. The action force acts on the second object, and the reaction force acts on the first object. This distinction is crucial for understanding how forces affect motion. Without reaction forces, many everyday phenomena, from walking to the operation of engines, would be impossible.