A free-body diagram (FBD) isolates one chosen body and shows only forces acting on that body. Draw the body as a point or box, identify every interaction, choose axes, resolve only after the force list is complete, and apply Newton’s law.

Do not draw velocity, acceleration, “centripetal force”, or the reaction force exerted by the selected body unless they are actual forces acting on it.

A free-body diagram depicts forces ON one isolated object BY other agents. On a block, draw its weight, surface normal, friction when relevant and applied push; omit the force that the block exerts on the surface because it acts on another object. Show force origins with labels such as ground on block, and draw components only after choosing axes. Inertial frames require only real interactions; accelerating frames may add a clearly identified pseudo force.

Worked example: For a block pushed right while kinetic friction points left, the horizontal equation is F−fk=ma, with vertical N−mg=0 on a level floor.

NCERT trap: Velocity and acceleration arrows are not additional forces in a free-body diagram.

NEET method: Circle the body, inventory its contacts and fields, then resolve only those force vectors.

Reading estimate excludes the first checks and the retake.

Laws of Motion

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