Free Body Diagrams, step by step
The method that prevents most mechanics errors.
- Isolate one bodyDraw it as a dot or a simple box.
- Draw every force acting ON itWeight, normal, tension, friction, applied, drag.
- Choose axesAlong the motion, or along the slope for an incline.
- Resolve into componentsmg sin θ down the slope, mg cos θ perpendicular.
- Apply ΣF = ma in each directionSeparately.
On a slope
- Down the slope: mg sin θ
- Into the slope: mg cos θ
- Normal reaction equals mg cos θ, not mg
The normal reaction on a slope is mg cos θ. Using mg is the single commonest error in inclined-plane problems.
Questions about the Free Body Diagrams poster
- What’s on the Free Body Diagrams poster?
- 5 numbered steps, with a full worked run-through. The method that prevents most mechanics errors. Isolate one body — Draw it as a dot or a simple box.; Draw every force acting ON it — Weight, normal, tension, friction, applied, drag.; Choose axes — Along the motion, or along the slope for an incline.; Resolve into components — mg sin θ down the slope, mg cos θ perpendicular.; Apply ΣF = ma in each direction — Separately.. The normal reaction on a slope is mg cos θ. Using mg is the single commonest error in inclined-plane problems.
- Who is the Free Body Diagrams poster for?
- Free Body Diagrams belongs to the Physics section rather than to a school year, because physical science is not something one grade owns. Anyone learning mechanics can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Free Body Diagrams poster?
- One body, every force on it, nothing else. Forces it exerts on other things do not belong. A wall chart earns its place by being glanceable from where the work is happening, so Free Body Diagrams belongs on the wall where that physical science work actually happens, within glancing distance, rather than filed away.
- What other posters go with Free Body Diagrams?
- Circular Motion, Friction & Drag and Gravitation sit alongside Free Body Diagrams in the Physics section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Circular MotionFriction & DragGravitation
- Is the Free Body Diagrams poster free to download and print?
- Yes. Free Body Diagrams downloads as a free PDF with no account, no email and no watermark, like everything else in the Physics section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Free Body Diagrams poster print at?
- Free Body Diagrams is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Free Body Diagrams loses nothing.Printing guide
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