Physics Calculator
Comprehensive physics calculations for kinematics, thermodynamics, energy, and wave physics
Kinematics Calculations
Use 9.81 for gravity
Physics Calculator: Kinematics, Energy, Thermodynamics & Wave Physics
Our Physics Calculator covers the core formulas across mechanics, thermodynamics, energy, and wave physics. Enter your known values and instantly solve for velocity, acceleration, force, work, pressure, wave speed, and more — with units and assumptions clearly shown.
Physics Formulas Reference
| Category | Formula | Variables | SI Units |
|---|---|---|---|
| Velocity | v = d/t | d=distance, t=time | m/s |
| Acceleration | a = (v−u)/t | v=final, u=initial vel. | m/s² |
| Newton's 2nd Law | F = ma | m=mass, a=acceleration | N |
| Work | W = F·d·cosθ | F=force, d=displacement | J |
| Kinetic Energy | KE = ½mv² | m=mass, v=velocity | J |
| Potential Energy | PE = mgh | g=9.81 m/s², h=height | J |
| Power | P = W/t | W=work, t=time | W |
| Pressure | P = F/A | F=force, A=area | Pa |
| Wave Speed | v = fλ | f=frequency, λ=wavelength | m/s |
| Ideal Gas Law | PV = nRT | n=moles, R=8.314 | Pa·m³ |
How to Use the Physics Calculator
- Select the physics category — choose from kinematics, dynamics, energy, thermodynamics, waves, or fluids.
- Choose the formula — select which variable to solve for; the calculator will show the corresponding form of the equation.
- Enter known values — input the values you know with their units. Unit conversion is handled automatically between SI and common alternatives.
- Review assumptions — kinematics assumes constant acceleration; thermodynamics assumes ideal gas unless noted. These are shown with each result.
- Check significant figures — results are rounded to match the precision of your input values.
Example Calculations
Example 1 — Projectile Motion
A ball is kicked horizontally at 20 m/s from a cliff 45 m high. Find time of flight and range.
- Vertical: h = ½gt² → t = √(2×45/9.81) = 3.03 s
- Horizontal range: x = v₀ × t = 20 × 3.03 = 60.6 m
Example 2 — Kinetic Energy of a Car
A 1,200 kg car traveling at 30 m/s (108 km/h).
- KE = ½ × 1,200 × 30² = ½ × 1,200 × 900 = 540,000 J = 540 kJ
- Stopping distance at 5,000 N braking: d = KE/F = 540,000/5,000 = 108 m
Frequently Asked Questions
What is the difference between speed and velocity?
Speed is a scalar quantity — it has magnitude only (e.g., 60 km/h). Velocity is a vector quantity — it has both magnitude and direction (e.g., 60 km/h north). A car driving in a circle at constant speed has changing velocity because the direction constantly changes. This distinction matters in kinematics: displacement (vector) vs distance (scalar) mirrors the velocity vs speed relationship.
What is Newton's second law of motion?
Newton's second law states F = ma: the net force on an object equals its mass times its acceleration. This means a heavier object requires more force to achieve the same acceleration, and a larger force produces greater acceleration on the same mass. In its full vector form, force and acceleration always point in the same direction. Weight (gravitational force) is a special case: F = mg where g = 9.81 m/s² near Earth's surface.
How do I calculate kinetic energy?
KE = ½mv² where m is mass in kilograms and v is speed in m/s. The result is in Joules. Note that KE depends on the square of velocity — doubling speed quadruples kinetic energy. This is why high-speed collisions are disproportionately more destructive. To convert to kWh (for energy storage problems): 1 kWh = 3,600,000 J.
What is the ideal gas law?
PV = nRT relates pressure (P in Pa), volume (V in m³), moles of gas (n), the universal gas constant (R = 8.314 J/mol·K), and absolute temperature in Kelvin (T = °C + 273.15). It models gases accurately at low pressures and high temperatures. At high pressures or low temperatures, use Van der Waals corrections for real gas behavior.
How is frequency related to wavelength?
Wave speed v = fλ, where f is frequency in Hz and λ is wavelength in meters. For a given medium (fixed wave speed), frequency and wavelength are inversely proportional — higher frequency means shorter wavelength. For light in a vacuum (c = 3 × 10⁸ m/s): a 500 nm visible light photon has frequency f = 3×10⁸ / 500×10⁻⁹ = 6 × 10¹⁴ Hz.
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