Ch 5 gives a rigorous treatment of Newton's laws — free body diagrams, friction (static and kinetic), applications to connected bodies (pulleys, inclined planes), and dynamics of circular motion.
First law: every body continues in its state of rest or uniform motion unless compelled by an external force. Second law: F = dp/dt = ma (net force = mass × acceleration, vector equation). Third law: action and reaction are equal and opposite, act on different bodies. Free body diagram: isolate each body, identify all forces (weight, normal, friction, tension, applied).
Static friction: opposes tendency of motion, f_s ≤ μ_s N (up to a maximum). Kinetic friction: opposes actual motion, f_k = μ_k N (generally μ_k < μ_s). Rolling friction: much less than sliding. On incline: normal N = mg cosθ; friction component along plane. Bank angle: tanθ = v²/rg for safe turning.
Download: https://ncert.nic.in/textbook/pdf/keph105.pdf | Part I: https://ncert.nic.in/textbook/pdf/keph1ps.zip
On a level road, only friction provides centripetal force. At high speeds, the required centripetal force (mv²/r) may exceed maximum friction (μmg), causing skidding. Banking tilts the road so that a component of the normal force (N sinθ) provides centripetal force. At the ideal banking angle, tanθ = v²/rg, and no friction is needed.
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