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Physics

20 calculators — Solve mechanics, optics, thermodynamics, and electrical circuit problems

Physics calculators covering kinematics, force, energy, waves, optics, thermodynamics, and electricity. Designed for students, engineers, and physics enthusiasts.

Acceleration

Acceleration Calculator

Calculate acceleration from initial velocity, final velocity, and time. Get instant results in m/s², plus the change in velocity, with a step-by-step breakdown shown.

Centripetal Force

Centripetal Force Calculator

Calculate centripetal force using F = mv²/r. Enter mass, velocity, and radius to instantly get the force keeping an object in circular motion.

Density

Density Calculator

Calculate density using ρ = m ÷ V. Enter mass and volume to instantly get density in kilograms per cubic meter, with a step-by-step formula breakdown.

Escape Velocity

Escape Velocity Calculator

Calculate the escape velocity of any celestial body using v = √(2GM/r). Enter mass and radius (Earth defaults included) to get results instantly.

Force

Force Calculator

Calculate force using Newton's second law, F = m × a. Enter mass and acceleration to get the resulting force in newtons instantly, with a step-by-step breakdown shown.

Free Fall

Free Fall Calculator

Calculate free fall time and final velocity from a drop height under gravity. Enter a height in meters to instantly get fall time and impact velocity, ignoring air resistance.

Frequency & Wavelength

Frequency & Wavelength Calculator

Calculate wavelength from wave speed and frequency using v = f × λ. Enter wave speed and frequency to instantly get wavelength in meters, for sound, light, or any wave.

Impulse

Impulse Calculator

Calculate impulse using J = F × t. Enter force and time duration to get impulse in newton-seconds instantly, equal to the resulting change in momentum produced.

Kinetic Energy

Kinetic Energy Calculator

Calculate kinetic energy using KE = ½mv². Enter mass and velocity to instantly get the energy of motion in joules, with a step-by-step formula breakdown.

Mechanical Power

Mechanical Power Calculator

Calculate mechanical power using P = W ÷ t. Enter work done and time taken to get power output in watts instantly, with a step-by-step breakdown.

Momentum

Momentum Calculator

Calculate linear momentum using p = m × v. Enter mass and velocity to get the resulting momentum in kg·m/s instantly, with a clear step-by-step breakdown shown.

Potential Energy

Potential Energy Calculator

Calculate gravitational potential energy using PE = mgh. Enter mass, height, and gravity to get stored energy in joules instantly, with an editable gravity field.

Pressure

Pressure Calculator

Calculate pressure using P = F ÷ A. Enter force and surface area to instantly get pressure in pascals, with a step-by-step formula breakdown.

Projectile Motion

Projectile Motion Calculator

Calculate projectile motion instantly — enter initial velocity and launch angle to get max height, time of flight, and horizontal range, with a trajectory diagram.

Specific Gravity

Specific Gravity Calculator

Calculate specific gravity by dividing a substance's density by a reference density (water by default). Instant unitless SG ratio with formula steps.

Speed

Speed Calculator

Calculate speed from distance and time instantly. Enter values in km, miles, or meters and hours, minutes, or seconds to get results in km/h, mph, and m/s at once.

Terminal Velocity

Terminal Velocity Calculator

Calculate an object's terminal velocity in free fall using mass, gravity, air density, cross-sectional area, and drag coefficient. Instant results.

Torque

Torque Calculator

Calculate rotational torque using τ = r × F × sin(θ). Enter lever arm length, force, and angle to get torque in newton-meters instantly, with a formula breakdown.

Velocity

Velocity Calculator

Calculate velocity from displacement and time, with direction shown instantly. Unlike speed, velocity is a vector — enter a signed displacement to see forward or backward motion.

Work

Work Calculator

Calculate mechanical work using W = F × d × cos(θ). Enter force, distance, and the angle between them to get work done in joules instantly.

About Physics Calculators

Physics calculators support quantitative problem-solving across the full breadth of classical and modern physics. From kinematics and Newton's laws to electricity, optics, and thermodynamics, the calculations in physics are precise and unforgiving — a sign error in a kinematics problem or a wrong unit in an electrical calculation leads to completely wrong answers. These tools let you verify working, check answers, and build physical intuition by seeing how results change with different inputs.

Mechanics and kinematics

Mechanics is the foundation of physics. The kinematic equations for uniform acceleration, Newton's three laws, energy conservation, and momentum form a tightly interconnected system. Understanding when to apply energy methods versus force methods — and recognising that both must give the same answer — deepens physical insight and reduces errors in complex problems.

Electricity and magnetism

Electrical calculations appear everywhere from Class 11 physics to JEE Advanced. Ohm's Law, Kirchhoff's Laws, RC and RL circuit analysis, and electromagnetic induction problems all require systematic application of formulas in the right sequence. Our circuit calculators help you set up problems correctly — particularly for complex networks where the series/parallel combinations are not immediately obvious.

Waves, optics, and sound

Wave physics is conceptually rich and mathematically elegant. The connection between frequency, wavelength, and wave speed; the conditions for constructive and destructive interference; the geometry of reflection and refraction — these concepts underpin not just physics exams but real technologies from optical fibres to noise-cancelling headphones. Lens and mirror calculations require careful sign convention discipline, which our calculators enforce.

Thermodynamics

Thermodynamics governs heat engines, refrigerators, phase transitions, and atmospheric processes. The laws of thermodynamics — energy conservation, entropy increase, absolute zero unreachability — have profound implications that are grounded in straightforward quantitative relationships. For JEE and competitive exam preparation, thermodynamics problems involving ideal gas processes (isothermal, adiabatic, isochoric, isobaric) are particularly important.

Frequently Asked Questions

What physics calculators are available on thecalcu.com?

thecalcu.com's physics category includes calculators for kinematics (velocity, acceleration, displacement), Newton's laws, energy and work, projectile motion, circular motion, waves and frequency, optics (refraction, lens equations), thermodynamics, electrical circuits (Ohm's law, power, resistance), and electromagnetism. These tools are designed for Class 11–12 students, JEE/NEET aspirants, and engineering undergraduates.

How do I calculate velocity, acceleration, and displacement using kinematic equations?

The four kinematic equations for constant acceleration are: (1) v = u + at; (2) s = ut + ½at²; (3) v² = u² + 2as; (4) s = (u + v)/2 × t — where u is initial velocity, v is final velocity, a is acceleration, s is displacement, and t is time. Choose the equation based on which variables are known and which is unknown. For a car decelerating from 72 km/h (20 m/s) to rest with acceleration −5 m/s²: using v² = u² + 2as, stopping distance = 400 ÷ 10 = 40 m.

How do I calculate projectile motion?

For a projectile launched at angle θ with initial speed u: horizontal velocity uₓ = u cos θ (constant throughout); vertical velocity uᵧ = u sin θ (decreasing due to gravity). Time of flight T = 2u sin θ ÷ g. Maximum height H = u² sin²θ ÷ (2g). Horizontal range R = u² sin 2θ ÷ g. Maximum range is achieved at θ = 45°. At g = 9.8 m/s², a ball kicked at 20 m/s at 45° has range = 400 × sin 90° ÷ 9.8 ≈ 40.8 m and maximum height ≈ 10.2 m.

How do I use Ohm's Law and calculate electrical power?

Ohm's Law: V = IR, where V is voltage (volts), I is current (amperes), and R is resistance (ohms). Electrical power: P = VI = I²R = V²/R (in watts). For a 60-watt bulb at 230 V (Indian mains voltage): current I = P/V = 60/230 ≈ 0.26 A; resistance R = V/I = 230/0.26 ≈ 885 ohms. Energy consumed in kWh = (P in watts × hours used) ÷ 1,000. A 1,000 W appliance running for 1 hour uses 1 unit (kWh) of electricity.

How do I calculate the period and frequency of a wave?

Frequency (f) = 1 ÷ Period (T), where T is in seconds and f is in hertz (Hz). Wave speed v = f × λ, where λ is wavelength. For sound in air at 25°C (speed ≈ 346 m/s): a 440 Hz note (musical note A) has wavelength = 346 ÷ 440 ≈ 0.786 m. For light (speed = 3 × 10⁸ m/s): green light at 550 nm has frequency = 3 × 10⁸ ÷ 550 × 10⁻⁹ ≈ 5.45 × 10¹⁴ Hz. The electromagnetic spectrum spans from radio waves (long λ, low f) to gamma rays (short λ, high f).

How do I calculate work, energy, and power in physics?

Work done W = F × d × cos θ, where F is force (N), d is displacement (m), and θ is the angle between force and displacement. Kinetic energy KE = ½mv². Potential energy PE = mgh. Power P = Work ÷ Time = Force × velocity. The work-energy theorem: net work done on an object equals its change in kinetic energy. For a 50 kg person climbing a 10 m staircase in 20 seconds: PE gained = 50 × 9.8 × 10 = 4,900 J; power = 4,900 ÷ 20 = 245 W ≈ 0.33 horsepower.

How do I calculate refraction and use the lens formula?

Snell's Law: n₁ sin θ₁ = n₂ sin θ₂, where n is the refractive index and θ is the angle to the normal. Refractive index n = c ÷ v = speed of light in vacuum ÷ speed of light in medium. The thin lens formula: 1/f = 1/v − 1/u (using sign convention: distances measured from the optical centre, positive to the right). Magnification m = v/u. For a convex lens of focal length 20 cm with an object at 30 cm: 1/v = 1/20 + 1/(-30)... using Cartesian sign convention, image forms at 60 cm, magnified by a factor of 2.

How do I calculate the force of gravity and gravitational potential energy?

Newton's Law of Gravitation: F = G × m₁ × m₂ ÷ r², where G = 6.674 × 10⁻¹¹ N m² kg⁻². Near Earth's surface, g ≈ 9.8 m/s² (varies slightly with latitude and altitude — it is 9.832 m/s² at the poles and 9.780 m/s² at the equator). Gravitational PE near Earth's surface: PE = mgh. At height h above Earth's radius R, the effective g = g₀ × (R/(R+h))². At 400 km altitude (ISS orbit), g ≈ 8.69 m/s² — astronauts are not weightless because gravity vanishes, but because they are in continuous free fall.

How do I calculate heat transfer and thermal expansion?

Heat transfer: Q = mcΔT, where m is mass (kg), c is specific heat capacity (J/kg·K), and ΔT is temperature change. Linear thermal expansion: ΔL = α × L₀ × ΔT, where α is the coefficient of linear expansion. For steel α ≈ 12 × 10⁻⁶ /°C — a 100 m steel bridge will expand by 1.2 mm for each 1°C rise. Volumetric expansion: ΔV = β × V₀ × ΔT, where β ≈ 3α. Expansion joints in bridges, railway tracks, and concrete roads are designed to accommodate these predictable thermal movements.

How do I calculate resistance in series and parallel circuits?

Series: Total resistance R_total = R₁ + R₂ + R₃ + … (current is the same through all resistors; voltage divides). Parallel: 1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + … (voltage is the same across all resistors; current divides). For two equal resistors R in parallel, R_total = R/2. Household wiring uses parallel circuits so each appliance operates at full mains voltage (230 V in India) regardless of other loads, and a blown fuse in one circuit does not affect others.

What is the formula for centripetal force and circular motion?

Centripetal acceleration: a = v² ÷ r = ω² × r, where v is linear speed, r is radius, and ω is angular velocity (rad/s). Centripetal force: F = mv² ÷ r = mω²r, directed toward the centre of the circle. Period T = 2πr ÷ v = 2π ÷ ω. For a car of 1,000 kg rounding a 50 m radius curve at 15 m/s (54 km/h): centripetal force = 1000 × 225 ÷ 50 = 4,500 N. The road's friction (or banked road's normal force component) must provide this force — this is why wet roads and sharp curves are dangerous at speed.