Getting Started With Basic Physics
Most people avoid physics because they think it requires advanced math they haven't learned yet. That's mostly true for college-level courses, but the foundation is simpler than you'd expect. You can start understanding how things move, interact, and behave without touching calculus. The trick is knowing where to begin and which concepts actually matter versus which ones are academic decorations. I've seen countless beginners quit after three weeks because they jumped straight into problems involving friction on inclined planes with rotating pulleys. That approach doesn't work. You build from the ground up, starting with units, measurements, and basic motion. Everything else depends on those fundamentals being solid. Start by learning the International System of Units (SI units). Length in meters, mass in kilograms, time in seconds. Get comfortable converting between them early. I once watched someone spend forty-five minutes on a simple kinematics problem because they didn't catch that their acceleration was given in kilometers per hour squared instead of meters per second squared. The problem was solvable in under five minutes once they converted properly. This happens constantly when you're first starting out.
After units, move to kinematics — the description of motion without worrying about forces. Position, velocity, acceleration. Learn the difference between speed and velocity right away. Speed is a scalar; it has magnitude only. Velocity is a vector; it has both magnitude and direction. Mixing these up causes errors that compound through every problem you attempt afterward. The three main kinematic equations are your starting toolkit:
- v = v + at
- x = x + vt + ½at²
- v² = v² + 2a(x - x)
These apply only when acceleration is constant. That's an important constraint. If acceleration changes over time, you need calculus-based methods, and that's a different path entirely. I've had students plug these equations into problems involving air resistance or variable force and then wonder why their answers were wrong. The equations weren't wrong. Their application was. Always check whether the constant-acceleration assumption holds before reaching for any of these formulas. Free fall is a special case of constant acceleration where a equals g, approximately 9.8 meters per second squared on Earth's surface. Objects dropped from rest near Earth's surface follow predictable patterns. Ignore air resistance for now. It complicates things unnecessarily at this stage, and real-world projectile problems in introductory courses usually assume a vacuum anyway. Once kinematics feels comfortable, transition to Newton's laws of motion. The first law introduces the concept of inertia and net force. The second law, F = ma, is the workhorse equation you'll use constantly. The third law deals with action-reaction pairs, and this is where most beginners stumble. Action-reaction pairs act on different objects, not the same object. When you push a wall, the wall pushes back on you with equal force. These forces don't cancel because they operate on separate bodies. I spent an entire weekend untangling this misconception after seeing it confuse multiple students. Writing out free-body diagrams for each object separately made it click.
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Free-body diagrams are non-negotiable. Draw every force acting on the object in question. Label magnitudes and directions. Omit forces that aren't actually present. Skip this step and you're guessing, not solving. I've reviewed solutions from people who claimed to understand the material but produced garbage answers, and ninety percent of the time the problem traced back to an incomplete or incorrect free-body diagram. Sometimes they included a normal force where none existed. Sometimes they forgot friction entirely. Sometimes they drew the force of gravity pointing sideways because they hadn't oriented their diagram correctly. When you reach forces, learn to resolve vectors into components. A force at an angle needs to be split into horizontal and vertical parts using sine and cosine. This skill connects directly to trigonometry, so make sure your trig fundamentals are solid before proceeding. If you're shaky on SOH CAH TOA, pause here and review. Everything downstream depends on it. Work, energy, and power come after forces. The work-energy theorem states that net work equals the change in kinetic energy. Conservation of energy is the broader principle. Potential energy converts to kinetic energy and back. Friction turns mechanical energy into heat, which is why perpetual motion machines don't exist. Simple concepts, but the bookkeeping matters. Track every form of energy in the system or your answer will be wrong.
For resources, the OpenStax Physics textbook is free and covers introductory material thoroughly. HyperPhysics provides concept maps that help connect ideas. YouTube channels like Michel van Biezen post problem-solving videos organized by topic. Practice problems matter more than passive reading. Do the problems. Check your work. Review where you went wrong. Repeat. The main limitation of self-study is the lack of immediate feedback. When you're stuck, you might sit on a problem for two hours assuming you're missing something obvious when the real issue is a sign error you introduced three steps back. Having someone check your work early and often prevents this. Online forums like Physics Forums can help, but verify any advice you receive against reliable sources. Some users give confident but incorrect answers on difficult problems. Another limitation is that introductory physics problems are idealized. Real surfaces aren't perfectly frictionless. Real strings don't have mass. Real pulleys don't have friction in their bearings. The models break down when you encounter real systems, but that's expected. The simplified models teach you the core principles. You add complexity later, once you understand the baseline behavior.
Don't rush. One concept per week is plenty for a serious beginner. Spend a week on units and conversions. Then kinematics. Then forces. Build each layer before adding the next. The people who quit are usually the ones who try to consume everything at once and end up understanding nothing well enough to apply it.
