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InformationUDP datagram service

UDP exchanges addressed messages without adding reliable stream delivery.

DefinitionInformationDNS names, records and caching

DNS distributes typed resource records through a delegated naming hierarchy.

DefinitionInformationCombinational digital-circuit model

A combinational output depends on current valid inputs after a bounded settling delay.

ModelInformationBoolean gates and truth tables

Logic gates compute Boolean functions with truth values 0 and 1.

DefinitionInformationClocked storage and sequential state

Sequential circuits retain state, so current inputs alone do not determine their behavior.

ModelInformationStored programs and instruction sets

Stored instructions control computation through a specified hardware/software interface.

ModelPhysicsDisplacement, distance and average speed

Displacement compares endpoints; distance measures the travelled path.

ModelPhysicsConstant-acceleration kinematics

Closed formulas require constant acceleration over the interval.

ModelPhysicsInertial reference frames and inertia

Newtonian force balances need an inertial frame or explicit inertial terms.

ModelPhysicsCircular motion and centripetal acceleration

A constant speed can still have an acceleration.

ModelPhysicsMass, gravitational weight and apparent weight

Mass is in kilograms; gravitational weight is a force.

ModelPhysicsNormal forces and tension

Contact geometry determines the force direction.

ModelPhysicsFree-body diagrams and system boundaries

List forces on the selected body once.

ModelPhysicsStatic and kinetic dry friction

Static friction is a responsive force with an approximate limit.

ModelPhysicsFluid drag and terminal speed

Terminal speed depends on the chosen drag model.

ModelPhysicsImpulse and momentum transfer

Time-integrated net force changes momentum.

ModelPhysicsElastic and inelastic collisions

Momentum conservation and kinetic-energy conservation are different.

ModelPhysicsConservative forces and potential energy

Potential-energy differences encode path-independent work.

ModelPhysicsMechanical-energy conservation and dissipation

Mechanical energy is only part of the total energy.

ModelPhysicsHooke’s spring model and elastic energy

A linear spring restores displacement toward equilibrium.

ModelPhysicsMechanical power

Power measures the rate of work or energy transfer.

ModelPhysicsRigid-body rotational kinetic energy

Rotation stores kinetic energy determined by mass distribution.

ModelPhysicsRolling without slipping

No slip constrains velocity at the contact point.

ModelPhysicsStatic equilibrium and torque balance

Zero net force alone does not prevent rotation.

ModelPhysics · Earth & cosmosYoung, shear and bulk elastic moduli

Stress and strain need a loading geometry and a constitutive range.

ModelPhysicsDensity and fluid pressure

Density is mass per volume; pressure is normal force per area.

ModelPhysicsAbsolute, gauge and differential pressure

A zero gauge reading need not be a vacuum.

ModelPhysicsPascal’s principle and ideal hydraulics

A pressure change is transmitted; pressure need not be equal at different heights.

ModelPhysicsNewtonian viscosity and Poiseuille flow

Viscosity relates shear stress to velocity gradient.

ModelPhysics · ChemistrySurface tension and capillary rise

Interface forces can support pressure jumps and capillary columns.

Model
ModelSource checked

Normal forces and tension

Physics

Contact geometry determines the force direction.

Key knowledge

A normal force is the perpendicular component of a contact force. Tension in an ideal flexible connector pulls along the connector; a slack ideal rope cannot transmit compression. The contact/tension magnitudes are solved from dynamics and constraints, rather than being universally equal to weight. A massless taut connector over a frictionless ideal pulley has the same tension magnitude along it.

Conditions and scope

  • Normal and tangential contact components refer to the stated local surface.
  • Equal tension uses the massless, taut, ideal connector and frictionless pulley assumptions; connector mass or pulley friction/inertia can change it.
Sources · 1

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. University Physics Volume 1, §5.6: common forcesSamuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)Textbook chapteropenstax.orgRead source

Evidence and review

Read §5.6 normal-force/incline and Tension body, including massless-rope and frictionless direction-change qualifications; exclude blanket claims that every contact force supports exactly mg.

2026-10-10 · /root/audit_life_earth_chemistry — independent Chemistry/Life/Earth editor. Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.

Related reference entries

Explore relationships within this area of study and its connections to other areas.

Showing 1–4 of 4 relationships

Scientific relationships · 4 / 4

The relationship type describes the connection. Its linked statements, sources and conditions define the scope.

  1. Uses definition
    Relationship sources · 1

    Linked statements

    • A normal force is the perpendicular component of a contact force. Tension in an ideal flexible connector pulls along the connector; a slack ideal rope cannot transmit compression. The contact/tension magnitudes are solved from dynamics and constraints, rather than being universally equal to weight. A massless taut connector over a frictionless ideal pulley has the same tension magnitude along it.

    This relation concerns the stated normal forces and tension claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  2. Related to
    Relationship sources · 1

    Linked statements

    • A normal force is the perpendicular component of a contact force. Tension in an ideal flexible connector pulls along the connector; a slack ideal rope cannot transmit compression. The contact/tension magnitudes are solved from dynamics and constraints, rather than being universally equal to weight. A massless taut connector over a frictionless ideal pulley has the same tension magnitude along it.

    This relation concerns the stated normal forces and tension claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  3. Uses definition
    Relationship sources · 1

    Linked statements

    • In the simple dry-contact model, static friction adjusts to prevent tangential relative slip up to |F_s|≤μ_sN. During sliding, kinetic friction has magnitude approximately μ_kN and opposes relative sliding at the contact. Static friction need not be at its limit and can accelerate a body or act in its direction of motion.

    This relation concerns the stated static and kinetic dry friction claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  4. Related to
    Relationship sources · 1

    Linked statements

    • Surface tension γ is force per unit effective contact-line length for a liquid interface. A thin soap film has two surfaces, so a movable wire of length ℓ feels 2γℓ. In a narrow circular vertical tube, static capillary height relative to a reservoir is approximately h=2γcosθ/(ρgr): wetting θ<π/2 raises the liquid, while θ>π/2 depresses it.

    The two records describe related physical or metrological models or distinctions; the present claim does not require every hypothesis or result in the linked record.

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