point particle

Examples of point particle in the following topics:

• Center of Mass and Translational Motion

  • The COM (center of mass) of a system of particles is a geometric point that assumes all the mass and external force(s) during motion.
  • By doing this, we have essentially considered a rigid body as a point particle.
  • This means that such bodies may not behave like a point particle, as earlier suggested.
  • We describe the translational motion of a rigid body as if it is a point particle with mass m located at COM.
  • By introducing the concept of COM, the translational motion becomes that of a point particle with mass m.

• Motion of the Center of Mass

  • We can describe the translational motion of a rigid body as if it is a point particle with the total mass located at the COM—center of mass.
  • We can describe the translational motion of a rigid body as if it is a point particle with the total mass located at the center of mass (COM).
  • You can see that the Newton's 2nd law applies as if we are describing the motion of a point particle (with mass M) under the influence of the external force.
  • In a system of particles, each particle may feel both external and internal forces.
  • The COM will orbit around the Sun as if it is a point particle.

• Electric Field from a Point Charge

  • The effect is felt as a force, and when charged particles are not in motion, this force is known as the electrostatic force.
  • Given a point charge, or a particle of infinitesimal size that contains a certain charge, electric field lines emanate radially in all directions.
  • Let's first take a look at the definition of the electric field of a point particle:
  • The electric field of a positively charged particle points radially away from the charge.
  • The electric field of a negatively charged particle points radially toward the particle.

• Stress and Strain

  • The effect is felt as a force and when charged particles are not in motion this force is known as the electrostatic force.
  • Given a point charge, or a particle of infinitesimal size that contains a certain charge, electric field lines emanate radially in all directions.
  • Let's first take a look at the definition of electric field of a point particle:
  • The electric field of a positively charged particle points radially away from the charge.
  • The electric field of a negatively charged particle points radially toward the particle.

• Particle-Wave Duality

  • Wave–particle duality postulates that all physical entities exhibit both wave and particle properties.
  • Wave–particle duality postulates that all physical entities exhibit both wave and particle properties.
  • From a classical physics point of view, particles and waves are distinct concepts.
  • Why then is it that physicists believe in wave-particle duality?
  • Because of its counter-intuitive aspect, the meaning of the particle-wave duality is still a point of debate in quantum physics.

• The Fields

  • We can use the potentials to determine the electric and magnetic fields produced by the moving particle.
  • It is important to remember that all of the properties of the particle are evaluated at the retarded time.
  • A few things to notice are that if the particle is not accelerating the electric field points to the current not the retarded position of the particle.
  • This allows us to graphically depict the field for a particle that is stopped suddenly.

• Center of Gravity

  • This is because the center of mass is at the point where people hold it up with their fingers.
  • The position of this force causes the object to act as a single point of force from the point.
  • When people think of objects, they think of them as singular particles of matter.
  • The different parts of the body have different motions. shows the motion of a stick in the air: it seems to rotate around a single point.
  • Specifically: 'the total mass x the position of the center of mass= ∑ the mass of the individual particle x the position of the particle. ' The center of mass is a geometric point in three-dimensional volume.

• Linear Expansion

  • (An example of this is the buckling of railroad track, as seen in . ) Atoms and molecules in a solid, for instance, constantly oscillate around its equilibrium point.
  • The answer can be found in the shape of the typical particle-particle potential in matter.
  • Particles in solids and liquids constantly feel the presence of other neighboring particles.
  • Fig 2 illustrates how this inter-particle potential usually takes an asymmetric form rather than a symmetric form, as a function of particle-particle distance.
  • In the diagram, (b) shows that as the substance is heated, the equilibrium (or average) particle-particle distance increases.

• Electric Potential Due to a Point Charge

  • The electric potential of a point charge Q is given by $V=\frac{kQ}{r}$.
  • The electric potential at a point is equal to the electric potential energy (measured in joules) of any charged particle at that location divided by the charge (measured in coulombs) of the particle.
  • Since the charge of the test particle has been divided out, the electric potential is a "property" related only to the electric field itself and not the test particle.
  • The electric potential due to a point charge is, thus, a case we need to consider.
  • Thus V for a point charge decreases with distance, whereas E for a point charge decreases with distance squared:

• Electric vs. Magnetic Forces

  • where B is the magnetic field vector, v is the velocity of the particle and θ is the angle between the magnetic field and the particle velocity.
  • The electric field lines from a positive isolated charge are simply a sequence of evenly-spaced, radially directed lines pointed outwards from the charge.
  • Charged particles will spiral around these field lines, as long as the particles have some non-zero component of velocity directed perpendicular to the field lines .
  • A magnetic field may also be generated by a current with the field lines envisioned as concentric circles around the current-carrying wire.The magnetic force at any point in this case can be determined with the right hand rule, and will be perpendicular to both the current and the magnetic field.
  • The electric field surrounding three different point charges: (a) A positive charge; (b) a negative charge of equal magnitude; (c) a larger negative charge.