Dr and dr with arrows in college physics, one is a vector and the other is an algebraic value. In college physics, arrows indicate directionality, and there are only algebraic values without arrows.

College physics is a basic course of university science and engineering. Through the study of the course, students are familiar with the basic laws of the structure, nature, interaction and movement of natural substances, and lay the necessary physical foundation for the further study of professional foundations and professional courses and the further acquisition of related knowledge. But engineering majors mainly teach mechanics and electromagnetism.