Leyes de Newton en Física

Introduction

• Newton's laws of motion describe the relationship between forces acting on an object and its motion. They are fundamental to classical mechanics.

Newton's First Law: Law of Inertia

• An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
• Inertia is the tendency of an object to resist changes in its motion.
• Mass is a measure of inertia. More massive objects have more inertia.
• The law is crucial for understanding why objects move the way they do in the absence of external forces. For example, a book resting on a table will remain at rest unless a force (like a hand pushing it) acts on it.

Newton's Second Law: Law of Acceleration

• The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
• This law is expressed mathematically as F = ma, where:
  • F is the net force acting on the object (measured in Newtons).
  • m is the mass of the object (measured in kilograms).
  • a is the acceleration of the object (measured in meters per second squared).
• The net force is the vector sum of all the forces acting on the object.
• The law means a larger force results in a larger acceleration, and a larger mass results in a smaller acceleration for the same force.

Newton's Third Law: Action-Reaction Law

• For every action, there is an equal and opposite reaction.
• Forces always come in pairs. If object A exerts a force on object B, then object B exerts an equal and opposite force on object A.
• These forces act on different objects.
• Examples include a rocket pushing against exhaust gases (the action), and the exhaust gases pushing back on the rocket (the reaction). Or a person pushing on a wall; the wall simultaneously pushes back on the person with an equal and opposite force.

Applications of Newton's Laws

• Newton's laws are used to analyze the motion of everyday objects, from a falling apple to a spacecraft orbiting the Earth.
• They are fundamental for engineering design, particularly involving vehicle motion and structural stability.
• They are also important in understanding phenomena in sports, from the trajectory of a ball to the motion of a swimmer.
• The principle of conservation of momentum is a key consequence of Newton's third law.
  • Momentum is a measure of an object's motion, and it is conserved if no external forces act on the system.