Newton's Second Law Calculator
Solve F = m·a for force, mass, or acceleration given the other two, with full unit handling (mass in kg, g, lb, oz; force in N, kN, lbf, kgf, dyn; acceleration in m/s², ft/s², g). Also compute weight W = m·g (gravity presets for Earth, the Moon, Mars, and Jupiter), momentum p = m·v, and kinetic energy KE = ½·m·v² from an optional velocity. Leave the one quantity blank to solve for it. Pairs with the Projectile Motion and Gear Ratio calculators for mechanics work. Everything runs locally in your browser.
Newton's second law F = m·a (1 newton accelerates 1 kg by 1 m/s²). Weight is the gravitational force on a mass, W = m·g; it varies with local gravity (Earth ≈ 9.80665, Moon ≈ 1.62, Mars ≈ 3.71, Jupiter ≈ 24.79 m/s²). Momentum p = m·v (kg·m/s) is conserved for isolated systems. Kinetic energy KE = ½·m·v² (joules). Unit conversions: 1 lb = 0.45359237 kg; 1 oz = 28.3495 g; 1 lbf ≈ 4.44822 N; 1 kgf = 9.80665 N; 1 dyn = 10 µN; 1 g (accel) = 9.80665 m/s²; 1 mph = 0.44704 m/s; 1 km/h = 0.277778 m/s; 1 ft/s = 0.3048 m/s. Everything runs locally — nothing leaves your browser.