Physics Calculators
Free calculators for force, kinematics, Ohm's law, projectile motion, flywheel energy, speed of light, and speed of sound. All equations with SI units.
Physics Calculators - Classical Mechanics and Electromagnetism, Solved
Physics calculators translate the fundamental laws of nature into numerical answers. Every calculator here applies the correct equation, shows all variable definitions with SI units, and walks through a worked example. Used by high school and undergraduate physics students.
Classical Mechanics
Electricity
Waves, Light, and Modern Physics
Rotational and Structural Mechanics
Engine and Machining Engineering
What These Calculators Cover
Classical mechanics. The Force Calculator applies Newton’s second law, and the Acceleration and Kinematics Calculators handle every motion problem built from a, v, u, s, and t. The Projectile Motion Calculator extends kinematics to two dimensions, and the Work, Energy & Power and Kinetic Energy Calculators close the loop between force, motion, and energy.
Electricity. The Ohm’s Law Calculator covers DC resistive circuits in all four V/I/R/P modes, while the AC Wattage and Power Dissipation Calculators extend into AC power factor and thermal design for real components, including junction temperature limits for transistors and MOSFETs.
Waves, light, and modern physics. The Speed of Light and Speed of Sound Calculators cover the two reference velocities behind every wave problem, while the Speed of Sound in Solids Calculator extends to the P-wave and S-wave speeds used in non-destructive testing. The Mirror Equation and Aperture Area Calculators cover geometric optics, and the Electron Speed Calculator bridges into relativistic and quantum territory alongside the dedicated particle physics and quantum mechanics sections.
Rotational and structural mechanics. The Mechanical Advantage Calculator covers the three classic simple machines, the Mohr’s Circle Calculator finds principal stresses for combined loading, and the Flywheel Energy Storage Calculator applies rotational kinetic energy to real energy-storage hardware. The Specific Heat Calculator rounds out the group with basic calorimetry.
Engine and machining engineering. The BMEP and Piston Speed Calculators work together for internal combustion engine performance analysis, and the Speeds and Feeds Calculator covers CNC machining parameters. The Darcy-Weisbach Calculator handles pipe head loss (the same physics as the fluid dynamics section’s Moody chart calculator), and the Ground Speed and Arrow Speed Calculators apply vector addition and empirical ballistics correction to real-world aviation and archery problems.
Who Uses These Calculators
High school students use the classical mechanics and electricity calculators directly against their curriculum. Undergraduate engineering students use the structural (Mohr’s circle) and machining (speeds and feeds, BMEP) tools for mechanical engineering coursework. Automotive engineers and engine builders use the BMEP and piston speed calculators to classify engine stress levels. Electricians and electronics engineers use the Ohm’s law, AC wattage, and power dissipation calculators for cable sizing and thermal design. Pilots and flight students use the ground speed calculator for wind-triangle navigation problems, and archery and bowhunting enthusiasts use the arrow speed calculator to estimate real-world kinetic energy for game classification.
Frequently Asked Questions
What does SUVAT stand for?
s = displacement, u = initial velocity, v = final velocity, a = acceleration, t = time. The Kinematics Calculator uses all five equations of motion to solve for any two unknowns given three known values.
Does the projectile motion calculator account for air resistance?
No - the Projectile Motion Calculator uses the ideal model (no drag, constant g = 9.81 m/s²). This is the standard physics curriculum model. Real-world trajectories at high speeds or long ranges will differ.
What is the difference between work and power?
Work (joules) is total energy transferred: W = F × d. Power (watts) is the rate: P = W/t. A motor lifting 100 kg by 10 m does 9,810 J of work regardless of speed. If done in 10 s, power = 981 W; in 5 s, power = 1,962 W. Calculate both with the Work Energy Power Calculator.
Can the Ohm's law calculator handle AC circuits?
The Ohm's Law Calculator applies V = IR for DC resistive circuits. For AC circuits with reactance, impedance Z replaces R. For electronics circuit design, also see the Voltage Divider and Transformer Ratio calculators.
What is the difference between BMEP and piston speed for engine analysis?
BMEP (Brake Mean Effective Pressure) measures how effectively an engine uses its cylinder volume to produce torque, independent of engine size - it lets you compare a small turbocharged engine against a large naturally aspirated one on equal footing. Mean piston speed measures purely mechanical stress from the piston's reciprocating motion, largely independent of power output. A well-tuned engine needs both figures in a healthy range: high BMEP with excessive piston speed risks mechanical failure, while low BMEP at safe piston speed means the engine is underutilized. Use the BMEP and Piston Speed Calculators together for a full picture.
Why does Mohr's circle work for stress transformation?
Mohr's circle is a graphical solution to the stress transformation equations, exploiting the fact that normal stress σ(θ) and shear stress τ(θ) at any rotated angle trace out a circle when plotted against each other, centered at the average normal stress (σx+σy)/2 with radius equal to the maximum shear stress. This lets you read off the principal stresses (where the circle crosses the σ-axis, τ=0) and the maximum shear stress (the circle's radius) without re-deriving the transformation equations for every angle. The Mohr's Circle Calculator computes these directly from σx, σy, and τxy.