[亚历克西·亚历克西维奇·马克拉科夫 (1872年9月19日 - 1918年3月21日) ]

Lev Vygotsky, a pioneering Russian psychologist, developed a theory of cognitive development that centers on the influence of social and cultural factors. Unlike Jean Piaget, who emphasized the child's direct interaction with the physical world as key to development, Vygotsky argued that cognitive growth is an interpersonal process that unfolds within a cultural context. For Vygotsky, a child's learning cannot be separated from their social environment, which includes the values,...

Overview

Vectors can be multiplied by scalars, added to other vectors, or subtracted from other vectors. The vector sum of two (or more) vectors is called the resultant vector or, for short, the resultant.
We use the laws of geometry to construct resultant vectors, followed by trigonometry to find vector magnitudes and directions. For a geometric construction of the sum of two vectors in a plane, we follow the parallelogram rule. Suppose two vectors are at arbitrary positions. Translate either one of...

In electrostatics, the electric field can be written as the negative gradient of the potential. In magnetostatics, the zero divergence of the magnetic field ensures that the magnetic field can be expressed as the curl of a vector potential. This potential is known as the magnetic vector potential.
Consider an ideal solenoid with n turns per unit length and radius R. If I is the current through the solenoid, the magnetic field inside the solenoid is expressed as the product of vacuum...

James Clerk Maxwell (1831–1879) was one of the major contributors to physics in the nineteenth century. Although he died young, he made major contributions to the development of the kinetic theory of gases, to the understanding of color vision, and to understanding the nature of Saturn's rings. He is probably best known for having combined existing knowledge on the laws of electricity and magnetism with his insights into a complete overarching electromagnetic theory, which is...

Work and power in rotational motion are completely analogous to work and power in translational motion. The total work done to rotate a rigid body through an angle 'θ' about a fixed axis is the sum of the torques integrated over the angular displacement. Hence, torque and angular displacement in rotational motion are analogous to force and linear displacement in translational motion, respectively.
Similarly, the power delivered to a system that is rotating about a fixed axis...