**X1**

X1 consists of educational physics articles in Persian. To see the (English) abstract of each article, no particular software is needed. But the full texts are in the pdf format. To view them, Adobe (Acrobat) reader 5 or later is needed. Adobe reader can be obtained from Adobe reader download.

**
Using, printing, and publishing these texts for non-commercial purposes is free,
provided they are not altered in any sense (including text, style, and orthography).
For any other use, author's permission is needed.**

X1-123 (2017/04/07) abs full text The central force and special relativity X1-122 (2017/02/25) abs full text The field-lines of a charge which moves on a straight line X1-121 (2017/01/27) abs full text The paradox of the drift velocity in matter

X1-120 (2016/11/27) abs full text The Galileo symmetry X1-119 (2016/10/29) abs full text The energy-momentum tensor III X1-118 (2016/08/27) abs full text The electric force on concentrated sources X1-117 (2016/07/28) abs full text Spinors and the curved space X1-116 (2016/05/26) abs full text The oblateness of the earth, the latitude, and the arc length X1-115 (2016/04/29) abs full text The maximally-symmetric spaces X1-114 (2016/02/25) abs full text The Frenet frame X1-113 (2016/01/28) abs full text The curvature, the volume, the area

X1-112 (2015/11/29) abs full text Two port circuits X1-111 (2015/10/30) abs full text Approximate action for the interaction of charged particles X1-110 (2015/08/28) abs full text Fitting, estimation, uncertainty II X1-109 (2015/07/30) abs full text Fitting, estimation, uncertainty I X1-108 (2015/05/29) abs full text A finite conducting rod X1-107 (2015/04/30) abs full text Angle-preserving and area-preserving planar maps of the sphere X1-106 (2015/02/20) abs full text The stationary shape of the surface of a moving fluid X1-105 (2015/01/24) abs full text The Green's function of the Laplacian for the space outside a disc

X1-104 (2014/11/28) abs full text Equilibrium of ordinary stars X1-103 (2014/10/30) abs full text Scattering in one dimension II X1-102 (2014/08/22) abs full text Degenerate perturbation X1-101 (2014/07/25) abs full text Estimating the mass and radius of degenerate stars X1-100 (2014/05/30) abs full text The geometry of Emission and absorbtion of radiation X1-099 (2014/04/25) abs full text Measurement, estimation, uncertainty X1-098 (2014/02/22) abs full text A falling liquid X1-097 (2014/01/31) abs full text Dipole density

X1-096 (2013/11/29) abs full text Stability of the atmosphere, and the height-dependence of the temperature X1-095 (2013/10/30) abs full text Mappings defined on SU(2) and SO(3) X1-094 (2013/08/31) abs full text The manifolds of the groups SU(2) and SO(3) X1-093 (2013/07/28) abs full text The image of a charge distribution X1-092 (2013/05/29) abs full text Time-dependent perturbation, eigenvalue shift, and survival X1-091 (2013/04/25) abs full text Relativistic particle in external fields X1-090 (2013/02/26) abs full text Motion of a spherically-symmetric ball on a plane X1-089 (2013/01/28) abs full text Measurement of the probability

X1-088 (2012/11/29) abs full text Symmetries of the nonrelativistic spacetime, as a contraction of symmetries of the relativistic spacetime X1-087 (2012/10/29) abs full text A cable which is hanging upwards from the earth X1-086 (2012/08/30) abs full text The geometry and dynamics of surfaces embedded in space X1-085 (2012/07/31) abs full text Axis symmetry in arbitrary dimesnion X1-084 (2012/05/26) abs full text Boosted circuits X1-083 (2012/04/27) abs full text The polarization and the phase of light X1-082 (2012/02/28) abs full text The magnetic field of a thin solenoid X1-081 (2012/01/19) abs full text Transverse-electric and transverse-magnetic fields

X1-080 (2011/11/28) abs full text Strain, Stress, and moduli X1-079 (2011/10/28) abs full text Distribution of charge between two conducting spheres tangent to each other X1-078 (2011/08/25) abs full text Gaussian optics and the transfer matrix X1-077 (2011/07/28) abs full text Analemma X1-076 (2011/05/25) abs full text Adiabatic invariants, and the pendulum's energy X1-075 (2011/04/29) abs full text The perihelion of the Earth in the orbit of the Sun X1-074 (2011/02/23) abs full text The potential in some problems with nonlocalized sources X1-073 (2011/01/25) abs full text Time as a dynamical variable

X1-072 (2010/11/26) abs full text Eigenexponents of passive circuits X1-071 (2010/10/21) abs full text Relativistic particle in a scalar field X1-070 (2010/08/20) abs full text Wave propagation in discrete space X1-069 (2010/07/28) abs full text The generator of translation in the box X1-068 (2010/05/27) abs full text The conformal transformation and the Poisson's problem in two dimensions X1-067 (2010/04/24) abs full text Simultaneous observers X1-066 (2010/02/26) abs full text Two charged conductiong spheres X1-065 (2010/01/28) abs full text The scalar potential of a tube with an azimuthal current

X1-064 (2009/11/28) abs full text Poincaré mappings and the priciples of special relativity X1-063 (2009/10/29) abs full text The internal energy of a relativistic ideal gas X1-062 (2009/08/19) abs full text Diagrammatics I X1-061 (2009/07/30) abs full text The de Hass-van Alphen effect in two dimensions X1-060 (2009/05/22) abs full text Virial and the van der Waals equation X1-059 (2009/04/24) abs full text Parallel transport in two dimensions X1-058 (2009/02/26) abs full text The statistical mechanics of the rotator X1-057 (2009/01/08) abs full text Thermodynamics of single particle interactions

X1-056 (2008/11/28) abs full text The semiclassical approximation X1-055 (2008/10/25) abs full text The dispersion relation of vector waves X1-054 (2008/08/27) abs full text Planets' lights X1-053 (2008/07/25) abs full text Rolling friction X1-052 (2008/05/29) abs full text Surface waves of liquids X1-051 (2008/04/29) abs full text Thomas precession X1-050 (2008/02/29) abs full text Relativity and constant acceleration X1-049 (2008/01/31) abs full text Relativity and systems with variable mass

X1-048 (2007/11/23) abs full text Wave propagation in moving media X1-047 (2007/09/13) abs full text The action and discrete time X1-046 (2007/07/31) abs full text Distillation and the composition of liquid and vapor X1-045 (2007/06/29) abs full text The triple point, and the vapour pressure X1-044 (2007/04/19) abs full text The Sagnac effect X1-043 (2007/02/28) abs full text The holomorphic picture of the harmonic oscillator X1-042 (2007/01/29) abs full text Evolution of continuous random variables

X1-041 (2006/11/17) abs full text A long cylinder floating on the surface of a liquid X1-040 (2006/09/29) abs full text The rotational states and the phase space X1-039 (2006/07/31) abs full text Towards a specific point on the sphere X1-038 (2006/06/29) abs full text Rigid body and special relativity X1-037 (2006/04/27) abs full text Space symmetries of the magnetic field X1-036 (2006/02/12) abs full text The time interval between two successive Moonsets X1-035 (2006/01/08) abs full text Uniformly-charged solid ellipsoid

X1-034 (2005/11/08) abs full text The spinor representations of so(4) X1-033 (2005/09/03) abs full text Escape of a gas through a small opening X1-032 (2005/07/30) abs full text Motion of a charge in a uniform and constant electromagnetic field X1-031 (2005/06/30) abs full text The sound barrier X1-030 (2005/04/12) abs full text The density matrix X1-029 (2005/02/20) abs full text The energy-momentum tensor II X1-028 (2005/01/07) abs full text The energy-momentum tensor I

X1-027 (2004/10/23) abs full text The area distribution of a submanifold X1-026 (2004/09/13) abs full text Why do stars twinkle? X1-025 (2004/07/23) abs full text Newton's laws X1-024 (2004/06/12) abs full text Newtonian cosmology X1-023 (2004/04/01) abs full text Scattering in one dimension I X1-022 (2004/02/21) abs full text Hydrogen-like ions, and spherical spinors X1-021 (2004/01/22) abs full text The electromagnetic field equations in matter

X1-020 (2003/11/20) abs full text The pressure-difference due to the surface tension, and the differential geometry of surfaces X1-019 (2003/09/29) abs full text The motion of a charged particle in an almost-homogeneous magnetic field X1-018 (2003/08/28) abs full text The effect of the Earth's atmosphere on the apparent size and shape of objects X1-017 (2003/06/08) abs full text Symmetry and the small oscillations X1-016 (2003/05/12) abs full text Symmetry and the Lagrangian formulation II X1-015 (2003/03/21) abs full text Symmetry and the Lagrangian formulation I X1-014 (2003/02/12) abs full text A bubble between two circular boundaries: a simple phase transition

X1-013 (2002/12/08) abs full text rigid body rotation, and the phase space formulation X1-012 (2002/10/04) abs full text Magnetic multipoles in magnetostatics X1-011 (2002/09/01) abs full text Birth of the modern quantum mechanics, in today's language X1-010 (2002/07/14) abs full text Elliptic coordinates in some electromagnetics problems X1-009 (2002/05/09) abs full text Oscillations of a body attached to a massive spring X1-008 (2002/03/21) abs full text How oblate is the Earth? X1-007 (2002/01/30) abs full text Transverse oscillations of a column of liquid

X1-006 (2001/12/21) abs full text Stochastic processes X1-005 (2001/10/03) abs full text The electrostatic potential, the potential-coefficients matrix, and the capacity matrix X1-004 (2001/08/01) abs full text Sundial X1-003 (2001/06/28) abs full text Green's functions of the Laplace and diffusion equation on the sphere and plane: contraction X1-002 (2001/04/01) abs full text Green's functions of the wave equation in different dimensions X1-001 (2001/02/21) abs full text Symmetries in quantum mechanics, and the degeneracy of the Hamiltonian