Category: Mechanics (Motion & Forces)

1. Introduction In physics, velocity is not absolute—it is always measured relative to a frame of reference. This is the core idea behind relative velocity. For example, if you are sitting inside a moving train and toss a ball straight up, the ball seems to move vertically up and down to you. But for someone…

Introduction Motion is one of the most fundamental concepts in physics. To describe motion effectively, scientists and students rely not only on equations but also on graphs. Graphs provide a visual representation of motion, making it easier to interpret the relationship between displacement, velocity, acceleration, and time. The three most important motion graphs are: Each…

Introduction One of the most fascinating aspects of physics is its ability to describe motion with just a few elegant mathematical relationships. Among these, the equations of motion hold a special place. They allow us to predict where an object will be, how fast it will move, and how long it will take to reach…

Introduction In physics, motion is one of the most fundamental concepts. To describe motion accurately, we need quantities that can measure how fast an object is moving and in which direction it is moving. These two aspects are captured by two important terms: speed and velocity. Although in daily language people often use speed and…

Introduction One of the most common and fascinating applications of Newton’s Laws of Motion in mechanics is the elevator problem. It deals with understanding how the tension in a string or the reading on a weighing machine (apparent weight) changes when an object is inside an elevator that is moving in different ways. The concept…

Introduction When we first learn Newton’s laws of motion in school, we usually focus on the obvious forces: gravity pulling everything downward, tension in a rope, friction that resists motion, and applied forces that push or pull objects. But there’s another force quietly working in the background, often overlooked and underappreciated: the normal force. The…

Introduction Every motion in the physical world is the result of forces. But forces alone are not enough — there also exists an opposing factor that resists or controls motion. This resisting influence is known as friction. Without friction, we would not be able to walk, vehicles could not run on roads, and almost every…

Introduction – What a Free-Body Diagram Is and Why It Matters Physics and engineering are built upon the study of forces—how they act on bodies, how they interact, and how they determine the motion or rest of objects. Yet when faced with real-world problems, the presence of multiple forces acting in different directions can easily…

Introduction Sir Isaac Newton’s Three Laws of Motion are the foundation of classical mechanics. While the First Law describes inertia and the tendency of objects to maintain their state, and the Second Law explains the relationship between force, mass, and acceleration, the Third Law gives us one of the most intuitive and famous principles in…

Introduction Sir Isaac Newton, one of the greatest scientific minds in history, forever changed the way we understand the physical world through his Three Laws of Motion, published in 1687 in his monumental book Philosophiæ Naturalis Principia Mathematica. While the First Law (Law of Inertia) explains the natural tendency of objects to resist changes in…