Fundamental Principles of Classical Physics and Dynamics

Fundamental Concepts of Force and Motion

Force: Every action can change the state of rest or motion of a body, or result in any deformation. Newton: The force that, when applied to a body of mass 1 kg, communicates an acceleration of 1 m/s².

Resultant Force: The vector sum of all forces in the system.

Conditions of Equilibrium

• Translational Equilibrium: For translational motion not to exist, the resultant of the system of forces that acts on the body should be null.
• Rotational Equilibrium: For rotational movement not to exist, the resultant moment of the system of forces that acts on the body must be zero.

Universal Gravitation and Electric Fields

Universal Law of Gravitation: Two material particles attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. Gravitational Field: The perturbation that a body makes in the space surrounding it due to the fact of having mass. Weight: The weight of an object is the force with which the Earth pulls it.

Coulomb's Law: The force of attraction or repulsion between two point electric charges is directly proportional to the product of the charges and inversely proportional to the square of the separation distance. Electric Field: The perturbation that a body makes in the space surrounding it due to the fact of having an electric charge.

Dynamics and Newton's Laws of Motion

Dynamics: The part of physics that studies the motion of bodies in relation to the forces that produce it.

• First Law: A body remains in its state of rest or uniform rectilinear motion if no force acts on it, or if the resultant force acting on it is zero.
• Second Law: If a resultant force acts on a body, it acquires an acceleration directly proportional to the applied force, with the body's mass being the proportionality constant.

Normal Force: The force exerted by the bearing surface of a body upon it. Friction: The force that appears on the contact surface of bodies, opposing their motion.

Physical Quantities and Kinematics

Scalars: Quantities determined by a numerical value and a unit of measurement (e.g., mass, temperature, power). Vector Quantities: Quantities determined if their magnitude (module) and direction are expressed (e.g., velocity, acceleration, force).

Reference Systems and Displacement

Mobile: A body in motion with respect to a particular reference system. Point Mass: A mobile without dimension, i.e., a point. Reference System: A point or set of points from which we describe the motion of a body. Displacement Vector: Between two points P₀ and P, it is the vector originating from P₀ and ending at P.

Velocity and Acceleration Components

Average Velocity Vector: The quotient of the displacement vector and the time interval. Instantaneous Velocity: The vector that the average velocity vector tends toward when the time interval tends to zero. Average Acceleration Vector: The ratio between the variation of the instantaneous velocity vector and the time interval between two points on the path.

• Tangential Component: It expresses the change in the magnitude of velocity.
• Normal Component: It expresses the change in the direction of the velocity.