César Mora | Searcharxiv

arXiv2012

Semi-quantitative diagram about temporal evolution in basic physics learning: a study with engineering students

We show a new semi-quantitative technique of analysis about of temporal evolution of learning of basic physics concepts. In this technique we arrange a geometric diagram with the score and the homogeneity (H-S), in this diagram we have a quantitative and qualitative information about the learning of students and the effectiveness instruction. We applied this technique to study the temporal evolution of the graphical interpretation of motion in one dimension through tutorials in a introductory course physics with 20 students of engineering at the Universidad Central de Bogotá Colombia for a period of 6 weeks. We found in the general diagram that (Smax,Hmax)=(0.75,0.75).

physics.ed-ph↗

arXiv2012

Estimation of solar illumination time on the earth by an analytical model: a fertile scenery for to teach physics

We proposed an analytical model for the calculus of illumination time of the Earth for any time of year and any latitude, this model assumes the obliquity of the ecliptic as constant, the light beams as parallels, the Earth as spherical, the movement of translation of Earth as uniform circular, also this model showed a context of the astronomy whereby the teachers can teach the basic physics.It was built through a relationship between the movement of translation and of rotation of the wave front light, then we found the of illumination zone on the Earth and the illumination time is estimated in a particular latitude with the uniform circular movement of Earth. Present model was confronted with the numerical results of the Geoscience Australia Agency and it is found a maxim perceptual error of 1,6%, this value was assigned primarily to the difference between the circular trajectory, in this model, and the elliptical trajectory that is the real. Without the use of spherical trigonometry was obtained an analytical model that estimates very close the solar illumination time at any time of year and any latitude on earth, the model provides an authentic context for studying basic aspects of physics.

astro-ph.EP↗

arXiv1998

Quantum Cosmology in some Scalar-tensor Theories

The Wheeler-DeWitt equation is solved for some scalar-tensor theories of gravitation in the case of homogeneous and isotropic cosmological models.We present general solutions corresponding to cosmological term: (i)λ(ϕ)=0$ and $(ii) λ(ϕ)=qϕ$.

gr-qc↗