🚀 Classical Mechanics
Newton's three laws, kinematics, forces, energy, momentum, rotation and gravitation — the foundation of all physics.
What you will learn
- Describe motion with velocity, acceleration and displacement
- Apply Newton's three laws to real situations
- Use work-energy and momentum conservation to solve problems
- Analyze circular motion, torque and gravitation
Study guide
High School concepts
Acceleration — Definition, Formula and Worked Examples
Acceleration is the rate of change of velocity: a = Δv/Δt. Units, vector direction, sign conventions, and worked examples from cars to free fall.
Center of Mass — The Balance Point That Moves Simply
The balance point of any object or system: how to locate the center of mass, why it moves as if all mass were there, and what that predicts.
Circular Motion and Centripetal Force Explained
Why circular motion needs a center-seeking force: a = v²/r and F = mv²/r, with examples from roundabouts to satellites.
Elastic Collisions in Detail — Conserving Momentum and Kinetic Energy
Collisions where kinetic energy is conserved: the defining conditions, the 1D equations, the equal-mass velocity swap, and worked examples.
Friction Force — Static vs Kinetic Friction Explained
Friction opposes sliding: static vs kinetic friction, the formula f = μN, the role of the normal force, and worked examples.
Newton's Law of Universal Gravitation — The Inverse-Square Force
Newton's law of universal gravitation: the inverse-square force between masses, the value of G, and why weight equals mg.
Inelastic Collisions in Detail — Lost Energy, Kept Momentum
Collisions where kinetic energy is not conserved: momentum still rules, perfectly inelastic sticking, energy-loss calculation, and explosions in reverse.
Kepler's Laws of Planetary Motion — Ellipses, Areas and Periods
Kepler's three laws of planetary motion — elliptical orbits, equal areas in equal times, and the T² ∝ a³ harmony — and how Newton explained them.
Conservation of Momentum — Collisions Explained
Momentum p = mv is conserved in collisions. Impulse, elastic vs inelastic collisions, and worked examples from car crashes to rockets.
Newton's First Law of Motion — Inertia Explained
Newton's first law: objects keep doing what they're doing unless a net force acts. Inertia, balanced forces, and why things stop on Earth.
Newton's Second Law — F = ma Explained with Examples
F = ma: how net force, mass and acceleration connect. Units, direction, net vs applied force, and worked examples from cars to rockets.
Newton's Third Law — Action and Reaction, Clearly Explained
For every action there is an equal and opposite reaction. What action-reaction pairs really are, why they don't cancel, and classic examples.
Projectile Motion Explained — Trajectories, Range and Height
Why thrown objects follow a curved path, the independence of horizontal and vertical motion, range and height formulas, and worked examples.
Simple Pendulum Motion — Period, Restoring Force and Timekeeping
How a swinging mass on a string keeps time: the restoring force, the period formula T = 2π√(L/g), and why mass and amplitude don't matter.
Static Equilibrium — Zero Net Force and Zero Net Torque
The two conditions for staying at rest — zero net force and zero net torque — with torque explained, seesaw and ladder examples, and stability.
The SUVAT Equations — Constant-Acceleration Kinematics
The five SUVAT equations for motion with constant acceleration: what s, u, v, a and t mean, how to choose the right equation, and fully worked examples.
Torque Explained — The Physics of Turning Things
Torque is τ = rF sin θ: why a longer wrench loosens bolts easier, how direction is found with the right-hand rule, and the rotational form of Newton's…
Work-Energy Theorem — Work Equals Change in Kinetic Energy
W = Fd and the work-energy theorem: net work equals change in kinetic energy. Derivation sketch, units, and worked examples.
Introductory College concepts
Angular Momentum Explained — L = Iω and Its Conservation
What angular momentum is, why L = Iω is conserved without external torque, and how skaters, divers and satellites exploit it.
Rotational Kinematics — Angular Displacement, Velocity and Acceleration
Angular displacement, velocity and acceleration: the rotational analogs of SUVAT, the radian, and how rotation connects to linear motion.
Formulas
L = Iω — Angular Momentum
Angular momentum equals moment of inertia times angular velocity.
Centripetal Force — F = mv²/r
The inward force needed for circular motion equals mass times speed squared divided by radius.
F = Gm₁m₂/r² — Newton's Law of Universal Gravitation
Gravitational force equals G times the product of the masses divided by the distance squared.
Gravitational Potential Energy — PE = mgh
Gravitational potential energy equals mass times gravity times height.
Hooke's Law — F = kx
The restoring force of a spring equals its stiffness times the displacement from equilibrium.
Kinetic Energy Formula — KE = ½mv²
Kinetic energy equals one-half times mass times velocity squared.
Momentum Formula — p = mv
Momentum equals mass times velocity.
Newton's Second Law — F = ma
The net force on an object equals its mass times its acceleration.
v = √(GM/r) — Circular Orbital Velocity
Orbital speed equals the square root of G times central mass over orbital radius.
T = 2π√(L/g) — Period of a Simple Pendulum
Period equals two pi times the square root of length over g.
Power Formula — P = W/t
Power equals work done divided by the time taken.
PE = ½kx² — Elastic Potential Energy of a Spring
Spring potential energy equals one-half times the spring constant times the stretch squared.
s = ut + ½at² — Displacement under Constant Acceleration
Displacement equals initial velocity times time plus one-half acceleration times time squared.
v = u + at — Velocity from Acceleration and Time
Final velocity equals initial velocity plus acceleration times time.
τ = rF·sinθ — Torque (Moment of Force)
Torque equals lever arm times force times the sine of the angle between them.
Work Formula — W = Fd
Work equals force times distance moved in the direction of the force.
Calculators
🧮 Acceleration Calculator
🧮 Angular Velocity Calculator — ω = Δθ/Δt
🧮 Centripetal Acceleration Calculator — a = v²/r
🧮 Escape Velocity Calculator — v = √(2GM/r)
🧮 Free Fall Calculator
🧮 Friction Force Calculator
🧮 Gravitational Force Calculator — F = Gm₁m₂/r²
🧮 Impulse Calculator — J = FΔt
🧮 Kinetic Energy Calculator
🧮 Momentum Calculator
🧮 Newton's Second Law Calculator (F = ma)
🧮 Orbital Velocity Calculator — v = √(GM/r)
🧮 Potential Energy Calculator
🧮 Power Calculator
🧮 Projectile Range Calculator
🧮 Speed and Velocity Calculator
🧮 Hooke's Law Calculator — F = kx
🧮 Elastic Potential Energy Calculator — PE = ½kx²
🧮 SUVAT Calculator — s = (u + v)t / 2
🧮 SUVAT Displacement Calculator — s = ut + ½at²
🧮 SUVAT Calculator — v² = u² + 2as
🧮 SUVAT Velocity Calculator — v = u + at
🧮 Torque Calculator — τ = rF sin θ
Simulations
Circular Motion Simulator
Spin a mass on a string: change the radius, speed and mass to discover exactly how centripetal force depends on each one.
InteractiveCollision Lab Simulator
Crash two carts head-on: set their masses and velocities, flip between elastic and sticky collisions, and verify momentum conservation.
InteractiveFree Fall Simulator
Drop objects from any height in a vacuum. Measure fall time and impact speed — and see why mass does not matter.
InteractiveInclined Plane Simulator
Slide a block down a ramp: tilt the angle, dial friction up and down, and watch the acceleration respond in real time.
InteractivePendulum Simulator
Swing a pendulum with any length, mass and angle. Verify that the period depends on length — not mass.
InteractiveProjectile Motion Simulator
Launch projectiles at any speed and angle. Watch the trajectory live and discover why 45° gives maximum range.
InteractiveSpring-Mass Oscillator Simulator
Stretch a spring-mass system with any stiffness and mass. Watch simple harmonic motion and test the period formula.
Practice
Circular Motion Practice
10 problems · 10 practice problems on circular motion — centripetal force, acceleration, orbital speed and banked …
Energy and Momentum Practice — Work, Power and Collisions
10 problems · 10 practice problems on work, energy, power and momentum — conservation laws, collisions and real ca…
Forces Practice — Newton's Laws Problems
10 problems · 10 practice problems on forces and Newton's laws — net force, inertia, friction and action-reaction …
Friction Practice Set 2
10 problems · 10 practice problems on friction — static vs kinetic, friction on inclines, and friction in accelera…
Gravitation Practice
10 problems · 10 practice problems on gravitation — Newton's law, orbital motion, escape velocity and weightlessne…
Kinematics Practice — Motion, Speed and Acceleration Problems
10 problems · 10 practice problems on kinematics — speed, velocity, acceleration and SUVAT equations — with instan…
Momentum and Collisions Practice 2
10 problems · 10 practice problems on momentum and collisions — elastic vs inelastic, impulse, and recoil.…
Projectile Motion Practice
10 problems · 10 practice problems on projectile motion — range, height, flight time and the independence of horiz…
SUVAT Equations Practice
10 problems · 10 practice problems on the SUVAT equations of uniformly accelerated motion — choosing the right equ…
Torque Practice
10 problems · 10 practice problems on torque — lever arms, balance, rotational equilibrium and the vector nature o…
Work and Energy Practice 2
10 problems · 10 practice problems applying the work-energy theorem — work by gravity, springs, brakes and power.…