Understanding Newton’s Laws of Motion

Posted on Nov 25, 2024 in Physics

Newton’s First Law of Motion (Inertia)

Every body perseveres in its state of rest or uniform rectilinear motion unless acted upon by external forces to change its state.

Newton’s Second Law of Motion (Force)

The change in motion is directly proportional to the applied force and occurs along a straight line in the direction of the force.

Newton’s Third Law of Motion (Action-Reaction)

For every action, there is an equal and opposite reaction. The mutual actions of two bodies are always equal and oppositely directed.

Physics (from Lat. Physica, and Gr. φυσική (ἐπιστήμη), physikḗ (epistḗmē)) is a natural science that studies the properties of space, time, matter, and energy, and their interactions.

Heat is a form of energy generated by chemical reactions (like combustion), nuclear reactions (like nuclear fusion within the Sun), electromagnetic dissipation (as in microwaves), or mechanical dissipation (friction). It’s linked to the Zeroth Law of Thermodynamics: two bodies in contact exchange energy until their temperatures equalize.

Thermal energy is energy released as heat. Sources include chemical reactions (exothermic reactions like fuel combustion), nuclear fission or fusion, electricity (Joule effect or thermoelectric effect), friction, and natural sources like geothermal or solar energy.

Speed is the physical quantity expressing an object’s change in position over time. It’s represented by v. Speed can be instantaneous, average, etc. The SI unit is meters per second (m/s).

Time measures the duration between events in a changing system. It allows us to order events sequentially (past, present, future) and underpins the principle of causality, a key axiom of the scientific method.

Temperature relates to the notions of hot and cold. Physically, it’s a scalar quantity linked to a system’s internal energy, specifically the “sensitive energy” associated with particle movement (translational, rotational, or vibrational). Higher sensitive energy means a higher temperature.

Force causes changes in an object’s speed or shape. Measured in Newtons (N), force is a vector quantity that can deform bodies, change their speed, or overcome inertia. It’s any action influencing an object’s motion or rest, causing acceleration or deformation.

Energy (from Greek ἐνέργεια/energeia, activity) represents the capacity to do work. In physics, it’s the ability to do work. In technology and economics, it’s a natural resource and its associated exploitation technology.

Gravity (gravitational force, gravitational interaction, or gravitation) is the theoretical force of attraction between objects with mass.