Physics
Mechanics, kinematics, optics and thermodynamics, with SI units enforced end to end. 67 tools, including Acceleration calculator, Angular Velocity Calculator, Banana radiation (equivalent dose) calculator and Bernoulli equation calculator. All free, with no account and nothing to install.
Acceleration calculatorCompute acceleration from the change in velocity over time.Angular Velocity CalculatorConvert RPM, rad/s, Hz and period, or derive ω from a linear speed and radius — with tangential speed and centripetal acceleration.Banana radiation (equivalent dose) calculatorPut any radiation dose in perspective with the Banana Equivalent Dose — the tiny ~0.1 µSv you get from the potassium-40 in one banana. Enter a dose in µSv, mSv, Sv, mrem or rem and it converts to bananas, standard units and a plain-language risk band.Bernoulli equation calculatorBernoulli's principle for an ideal fluid: pressure + kinetic + potential head stays constant along a streamline, P + ½ρv² + ρgh = constant. Give the conditions at two points and leave one unknown — pressure, velocity or elevation — and it solves for it, revealing how a pipe that narrows speeds the flow and drops the pressure.BPM delay time calculatorTurn a track's tempo into delay and reverb times in milliseconds.Buoyancy calculatorWill it float or sink? Archimedes' principle: the buoyant force equals the weight of the displaced fluid, F = ρ·V·g. From the fluid density, the object's volume and mass, it computes the buoyant force, the weight, the net force, the object's density, the float/sink verdict and — if it floats — the fraction that sits below the surface.Centripetal force calculatorCompute the centripetal force on an object moving in a circle (F = mv²/r).Coulomb's Law CalculatorSolve F = kq₁q₂/εᵣr² for the force, either charge or the distance, in any of 18 dielectric media, with charges in C, µC, nC or elementary charges, plus the potential energy and the field at q₂.de Broglie Wavelength CalculatorCompute λ = h/p for an electron, proton, neutron, alpha particle, C₆₀ or any mass, from a velocity or a kinetic energy, using the relativistic momentum p = γmv.Decibel (dB) CalculatorConvert power and voltage ratios to decibels and back, and switch between dBm, dBW, watts and milliwatts.Density calculatorCompute density from mass and volume (ρ = m / V).Displacement calculatorCompute displacement from initial velocity, acceleration and time (s = ut + ½at²).Doppler Effect CalculatorWork out the perceived frequency for a moving source or observer, classically f' = f(v ± v_o)/(v ∓ v_s) with real sound speeds, or relativistically for light — supersonic sources flagged.E = mc² Calculator (Mass–Energy)Convert mass into energy and back with a realistic efficiency — 100 % for antimatter, 0.7 % for fusion, 0.09 % for fission — and read the result in joules, kWh, kcal and tonnes of TNT.Efficiency calculatorCompute efficiency as the ratio of useful output to total input.Engine displacement calculatorCompute an engine's displacement from its bore, stroke and number of cylinders.Escape velocity calculatorCompute the escape velocity of a body from its mass and radius.Falling through the Earth calculator (gravity tunnel)Jump into a frictionless tunnel bored through the Earth — how long to reach the other side? For a uniform Earth the motion is simple harmonic, so any straight chord takes the same ~42 minutes one way, with a peak speed of ~7.9 km/s through the centre. Switch to the PREM density model for the realistic ~38-minute figure.Force calculator (F = ma)Compute force from mass and acceleration using Newton's second law.Free fall calculatorCompute the fall time and impact velocity of an object dropped from a height.Frequency & period calculatorConvert a frequency into its period (T = 1 / f) in seconds and milliseconds.Friction force calculatorCompute the friction force from the coefficient of friction and the normal force (F = μN).Gravitational force calculatorCompute the gravitational attraction between two masses (Newton's law).Heat transfer rate calculatorThe rate of heat flow by any of the three mechanisms: conduction through a wall (Q = k·A·ΔT/d), convection from a surface (Q = h·A·ΔT), or radiation between bodies (Q = ε·σ·A·(T₁⁴ − T₂⁴), with temperatures in kelvin). Pick a mode; only its fields matter.Helium balloon lift calculatorHow many helium balloons does it take to lift something? Each balloon size has a measured net lift, and thinner air at altitude reduces it. Enter the weight to lift, pick a balloon type and altitude, and it returns the number of balloons required and the total lift they provide.Hooke's law calculatorCompute the force of a spring from its stiffness and displacement (F = kx).Hydraulic Cylinder Force CalculatorPush and pull force of a hydraulic cylinder from F = P × A, with the rod annulus handled properly, the area ratio φ and an ISO bore table.Impulse calculatorCompute impulse from a force applied over a time (J = F·t).Inclined Plane CalculatorDoes the block stay or slide? Normal force, down-slope force, static and kinetic friction, the arctan μs tipping point, acceleration, slide time and final speed.Kepler's Third Law CalculatorGet the orbital period from T = 2π√(a³/GM) with the semi-major axis in AU, km or solar radii and the central mass in solar, Earth or Jupiter masses — plus orbital speed and the a³/T² constant.Kinematics CalculatorEnter any 3 of initial/final velocity, acceleration, time and displacement — the SUVAT equations solve the rest.Kinetic energy calculatorCompute kinetic energy from mass and velocity (½mv²).Kinetic energy chicken cookerA famous physics joke, made calculable: could you cook a chicken by throwing it? Each throw deposits kinetic energy ½mv²; cooking it needs enough heat to raise it to 74 °C (Q = m·c·ΔT). It reports the energy per throw and how many throws — at your chosen speed — the meal would take.Light travel time calculatorFind how long light takes to travel a distance in space.Magnetic field of a current calculatorThe magnetic flux density B produced by a current, for three classic geometries: a long straight wire (B = μ₀I/2πr), the centre of a single circular loop (B = μ₀I/2R) and inside a long solenoid (B = μ₀nI). Choose the geometry and enter the current; only that mode's fields matter.Mechanical Advantage CalculatorMechanical advantage of a lever, pulley, ramp or gear pair, with lever classes, the effort a load actually needs and the friction efficiency takes away.Moment of Inertia CalculatorArea moment (mm⁴, beam bending) and mass moment (kg·m², rotation) for 15 shapes, with the parallel-axis theorem and a live dimensioned diagram.Momentum calculatorCompute momentum from mass and velocity (p = mv).Musical note frequency calculatorCompute a note's frequency a number of semitones from a reference pitch (A4).Orbital period calculatorCompute how long an object takes to orbit a body from the orbit radius and mass.Orbital velocity calculatorCompute the circular orbital velocity around a body from its mass and orbit radius.Pendulum period calculatorCompute the swing period of a simple pendulum from its length (T = 2π√(L/g)).Penny drop impact calculatorWould a penny dropped from a skyscraper really kill someone? This tool applies quadratic air drag to find the terminal velocity a coin actually reaches, its true impact speed after any fall height, and the kinetic energy — debunking the famous myth with physics.Photon Energy CalculatorEnter a wavelength, a frequency or an energy and get all three from E = hf = hc/λ, in eV, keV, MeV and joules, with the spectral band named and the colour identified for visible light.Potential energy calculatorCompute gravitational potential energy from mass, height and gravity (E = mgh).Power calculator (physics)Compute power from work done over a period of time (P = W / t).Pressure calculatorCompute pressure from a force applied over an area (P = F / A).Projectile Motion CalculatorFrom launch speed and angle, compute range, max height, flight time and impact speed — with gravity presets for the planets.Pulley System CalculatorEffort, rope pulled and work in a block and tackle, with sheave friction compounding so you can see ideal and real mechanical advantage diverge.LC resonant frequency calculatorCompute the resonant frequency of an LC circuit from inductance and capacitance.Reynolds number calculatorThe Reynolds number tells you whether a flow is smooth (laminar) or chaotic (turbulent): Re = ρ·v·L / μ, the ratio of inertial to viscous forces. Enter the velocity, a characteristic length and the fluid's density and viscosity — or pick a fluid — and it returns Re and the flow regime for pipes, plates or channels.Snell's Law CalculatorSolve n₁sin θ₁ = n₂sin θ₂ for either angle or either index, get the critical angle, and watch the incident, reflected and refracted rays move on a live diagram — total internal reflection included.Specific heat calculatorCompute the heat energy needed to change a substance's temperature (Q = mcΔT).Speed of sound calculatorHow fast sound travels — through air at a given temperature (c ≈ 331.3·√(1+T/273.15) m/s, a touch faster in humid air), or through another medium from a reference table (water ~1481 m/s, steel ~5960 m/s). Results in m/s, km/h and mph, with the Mach-1 reference.Spring constant calculator (Hooke's law)Hooke's law three ways: solve for the spring constant k = F/x, the restoring force F = k·x, or the displacement x = F/k. It handles single springs and N identical springs in series (k/N) or parallel (N·k), and adds the stored elastic energy ½kx².Spring potential energy calculatorCompute the elastic potential energy stored in a spring (E = ½kx²).Thermal expansion calculatorCompute how much a material expands with temperature (ΔL = αLΔT).Lens Equation Calculator (Thin Lens)Solve 1/f = 1/u + 1/v for the image distance, focal length or object distance, with magnification, image height, real-vs-virtual verdict and a live three-ray diagram.Time Dilation CalculatorCompute γ = 1/√(1 − v²/c²), the traveller's time against the observer's, length contraction and the relativistic mass factor — with enough precision to show the 10⁻¹³ effect at everyday speeds.Torque calculatorCompute torque from a force applied at a distance from the pivot (τ = F·d).Velocity CalculatorFind velocity, distance, time, relative or angular-to-linear speed — five modes, any units.Wave speed calculatorCompute wave speed from frequency and wavelength (v = fλ).Weight from mass calculatorCompute the weight (force of gravity) of an object from its mass (W = mg).Weight on other planets calculatorFind out how much you would weigh on another planet or the Moon.Work and Power CalculatorCompute work (W = F·d·cosθ) and power (P = W/t) with full unit conversions.Work done calculatorCompute the work done by a force over a distance (W = F·d).Young's modulus calculatorCompute Young's modulus from a force, cross-section, length and extension.