Dynamics

Force, Mass, and Newton's Laws

Dynamics is the study of forces and their effects on motion. It is foundational for understanding natural phenomena and analyzing physical systems.

• Force: A vector quantity representing a push or pull, measured in newtons (N).

• Mass: A scalar quantity indicating the amount of matter and resistance to motion (inertia).

• Newton's First Law (Inertia): Objects remain at rest or in uniform motion unless acted upon by a net external force.

• Newton's Second Law: (Force equals mass times acceleration).

• Newton's Third Law: For every action, there is an equal and opposite reaction.

Free-Body Diagrams

Visual tools to analyze all forces acting on a single object, including gravity, normal force, friction, tension, and applied forces.

Contact Forces: Normal and Friction Forces

• Normal Force: Perpendicular force exerted by a surface, often balancing weight.

• Friction Force: Opposes motion; can be static (prevents motion) or kinetic (opposes ongoing motion). Depends on surface nature and normal force.

Linear Momentum and Impulse

• Momentum: (product of mass and velocity).

• Impulse: (change in momentum over time interval).

Conservation of Momentum

• In a closed system, total momentum remains constant if no external forces act: .

Electric Currents

Electric Current, Ohm’s Law, Resistance, and Resistors

Electric current is the flow of charge through a conductor, driven by potential difference.

• Electric Current: (rate of charge flow, measured in amperes).

• Ohm's Law: (voltage equals current times resistance).

• Resistance: (depends on material, length, area, and temperature).

• Resistors: Components designed to provide resistance in circuits.

Electric Power

• (power equals voltage times current).

• Alternate forms: or .

EMF and Terminal Voltage

• EMF: Energy per unit charge provided by a source (measured in volts).

• Terminal Voltage: (actual voltage across terminals, accounting for internal resistance).

Electric Field

Electric Charge, Static Electricity, and Induced Charge

• Electric Charge: Fundamental property; like charges repel, opposite attract. Measured in coulombs (C).

• Static Electricity: Accumulation of charge on surfaces, often due to friction.

• Induced Charge: Redistribution of charges in a conductor exposed to an external field.

Electric Field and Field Lines

• Electric Field: (force per unit charge).

• Field Lines: Visual representation; originate from positive, terminate at negative charges. Density indicates field strength.

Electric Potential, Voltage, and Equipotential Lines

• Electric Potential: Work required to bring unit charge from infinity; measured in volts.

• Voltage: Potential difference between two points.

• Equipotential Lines: Lines of constant potential, perpendicular to field lines.

Coulomb’s Law

• (force between two point charges).

Conductors, Dielectrics, and Charge Distribution

• Conductors: Charges move freely; redistribute to cancel internal field.

• Dielectrics: Insulators; become polarized in a field, reducing effective field strength.

• Charge Distribution: Charges accumulate on surfaces, especially at sharp edges.

Capacitance and Storage of Electric Energy

• (capacitance, measured in farads).

• Energy stored: .

Fluids and Solids

Mass, Weight, Density, and Specific Gravity

• Mass: Amount of matter (kg).

• Weight: (force due to gravity).

• Density: (mass per unit volume).

• Specific Gravity: Ratio of substance's density to water's density.

Pressure, Pascal’s Principle, and Hydraulic Lift

• Pressure: (force per unit area).

• Pascal’s Principle: Pressure change in a confined fluid is transmitted equally.

• Hydraulic Lift: (small force on small area creates large force on large area).

Archimedes’ Principle and Buoyancy

• Buoyant Force: (upward force equals weight of displaced fluid).

Elasticity, Stress, Strain, Hooke’s Law, and Young’s Modulus

• Stress: (force per unit area).

• Strain: (relative deformation).

• Hooke’s Law: (E = Young’s Modulus).

Geometrical Optics and Wave Nature of Light

Ray Model, Reflection, and Mirrors

• Ray Model: Light travels in straight lines (rays).

• Reflection: (angle of incidence equals angle of reflection).

• Plane Mirrors: Form virtual, upright images.

• Spherical Mirrors: Concave (converging), convex (diverging).

Total Internal Reflection and Fiber Optics

• Critical Angle: (for ).

• Fiber Optics: Use total internal reflection for light transmission.

Refraction and Snell’s Law

• (Snell’s law).

• (index of refraction).

Thin Lenses, Focal Point, and Optical Power

• Focal Point: Where parallel rays converge.

• Focal Length: Distance from lens to focal point.

• Optical Power: (measured in diopters).

Wave Nature: Huygens Principle, Diffraction, Interference, Polarization

• Huygens Principle: Every point on a wavefront acts as a source of secondary wavelets.

• Diffraction: Bending of light around obstacles/apertures.

• Interference: Overlapping waves produce constructive/destructive patterns.

• Polarization: Orientation of light wave oscillations; used in filters and imaging.

Kinematics

Vectors, Scalars, and Vector Components

• Scalars: Magnitude only (e.g., mass, speed).

• Vectors: Magnitude and direction (e.g., displacement, velocity).

• Components: , .

• Vector Addition: , , .

Frames of Reference and Displacement

• Frame of Reference: Perspective for observing motion.

• Displacement: Vector from initial to final position.

Velocity and Acceleration

• Velocity: .

• Acceleration: .

Motion at Constant Acceleration

Falling Objects and Projectile Motion

• Free Fall: (acceleration due to gravity).

• Projectile Motion: Horizontal (constant velocity), vertical (accelerated by gravity).

• Time of Flight:

• Maximum Height:

• Range:

Magnetism and Electromagnetic Induction

Magnets and Magnetic Fields

• Magnetic Field: Region where magnetic forces are observed; measured in teslas (T).

• Field Lines: Originate from north, terminate at south pole.

Magnetic Field of Wires and Coils

• Straight Wire: Magnetic field forms concentric circles; right-hand rule applies.

• Solenoids: Coils produce uniform field inside; enhanced by ferromagnetic core.

Force on Current and Moving Charge

• Lorentz Force:

• Force on Wire:

Faraday’s Law and Lenz’s Law

• Faraday’s Law: (EMF induced by changing magnetic flux).

• Lenz’s Law: Induced current opposes change in magnetic flux.

Electric Generators, Transformers, and Power Transmission

• Generators: Convert mechanical to electrical energy via induction.

• Transformers: (voltage ratio equals turns ratio).

• Power Transmission: High voltage reduces energy loss.

Electromagnetic Waves and Spectrum

• Electromagnetic Waves: Oscillations of electric and magnetic fields; speed m/s.

• Spectrum: Radio, microwave, IR, visible, UV, X-ray, gamma.

• Production: Accelerating charges emit EM waves.

Nuclear Physics and Radioactivity

Structure and Properties of the Nucleus

• Nucleus: Contains protons and neutrons (nucleons).

• Nuclear Size: , fm.

• Nuclear Forces: Strong force binds nucleons; acts over short distances.

Radioactivity: Alpha, Beta, Gamma Decay

• Alpha Decay: Emission of (helium nucleus).

• Beta Decay: Emission of electron/positron; changes atomic number.

• Gamma Decay: Emission of high-energy photons; no change in atomic/mass number.

Law of Radioactive Decay and Half-Life

• (exponential decay).

• Half-life:

Nuclear Reactions, Fission, Fusion, Reactors

• Transmutation: Element changes via nuclear reaction.

• Fission: Heavy nucleus splits, releasing energy and neutrons.

• Fusion: Light nuclei combine, releasing energy ().

• Reactors: Controlled fission for energy and isotope production.

Sounds

Characteristics of Sound

• Frequency: Number of cycles per second (Hz); determines pitch.

• Wavelength: Distance between compressions/rarefactions.

• Speed: Depends on medium; ~343 m/s in air.

• Amplitude: Maximum displacement; relates to intensity.

• Period:

Sound Intensity and Intensity Level

• (power per unit area).

• Intensity level: , W/m2.

Ear and Sound Loudness

• Outer, middle, inner ear process sound; loudness is subjective and frequency-dependent.

Doppler Effect

• (frequency shift due to relative motion).

Sources of Sound: Vibrating Strings and Air Columns

• Strings:

• Open pipes: ; closed pipes:

Standing Waves

• Nodes (no displacement) and antinodes (max displacement); fundamental and harmonics.

Temperature and Kinetic Theory of Gases

Temperature and Molecular Interpretation

• Temperature: Average kinetic energy;

• Kelvin scale: Absolute temperature.

Thermal Equilibrium and Zeroth Law

• If two systems are each in equilibrium with a third, they are in equilibrium with each other.

Ideal Gas Law

• (pressure, volume, moles, gas constant, temperature).

Heat and Internal Energy

• Heat: Energy transfer due to temperature difference.

• Internal energy for ideal gas:

First Law of Thermodynamics

• (change in internal energy equals heat added minus work done).

Specific Heat and Latent Heat

• Specific heat:

• Latent heat:

Heat Engines and Second Law

• Efficiency:

• Second law: Entropy increases; heat flows from hot to cold.

Vibration and Waves

Simple Harmonic Motion (SHM)

• Restoring force:

• Displacement: ,

Energy in SHM

• Kinetic:

• Potential:

• Total:

Simple Pendulum

• Period:

Resonance and Forced Vibration

• Resonance: Amplitude increases when driving frequency matches natural frequency.

Wave Motion

• Transverse: Oscillations perpendicular to propagation (e.g., light).

• Longitudinal: Oscillations parallel (e.g., sound).

• Wave speed:

Energy Transported by Waves

• Energy proportional to amplitude squared.

Propagation: Reflection, Refraction, Diffraction

• Reflection: Angle of incidence equals angle of reflection.

• Refraction: Bending due to speed change in different media.

• Diffraction: Spreading around obstacles/openings.

Work, Power, and Energy

Work

• (force times displacement in direction of force).

Kinetic and Potential Energy

• Kinetic:

• Potential: (gravitational), (elastic)

Power

• (work per unit time),

Conservative and Non-Conservative Forces

• Conservative: Path-independent (e.g., gravity, springs).

• Non-conservative: Path-dependent, dissipate energy (e.g., friction).

Conversion of Mechanical Energy

• (if only conservative forces).

Energy Transformations

• Mechanical, thermal, chemical, electrical; can convert between forms.

Work-Energy Principle

Additional info: These notes integrate key definitions, formulas, and applications relevant to medical studies, including examples and context for each topic. For tables, see the formulas and comparisons described in text. Applications in medicine are highlighted throughout, connecting physics principles to diagnostic and therapeutic technologies.