{"id":588,"date":"2026-07-17T11:20:14","date_gmt":"2026-07-17T11:20:14","guid":{"rendered":"https:\/\/physicsfundamentalsinfo.com\/blog\/?p=588"},"modified":"2026-08-24T13:04:03","modified_gmt":"2026-08-24T13:04:03","slug":"physics-formulas","status":"publish","type":"post","link":"https:\/\/physicsfundamentalsinfo.com\/blog\/mechanics\/physics-formulas\/","title":{"rendered":"Physics Formulas: The Complete Cheat Sheet"},"content":{"rendered":"\n
Definition<\/div>

\nPhysics formulas are compact equations that state exactly how measurable physical quantities depend on one another, such as force equals mass times acceleration. Each symbol stands for a quantity with its own SI unit, so a formula is both a calculation rule and a statement about how the physical world behaves.\n<\/p><\/div>\n\n

Open any physics textbook to the inside back cover and you meet a wall of equations. Dozens of them, packed shoulder to shoulder, with no hint about which ones matter or how they connect. It reads like a list to be memorised. It isn’t.<\/p>\n\n

Here is what actually happens in an exam hall. You know the physics cold \u2014 and then you stall, because you cannot recall whether it was v2<\/sup> = u2<\/sup> + 2as or v2<\/sup> = u2<\/sup> + 2at, and you have ninety seconds to choose. That moment is what this page is built for.<\/p>\n\n

What Are Physics Formulas?<\/h2>\n\n

A physics formula is a compact statement that one physical quantity is fixed by other physical quantities in an exact, testable way. Not a rule of thumb. Not an approximation someone found convenient. A claim about reality that experiment can break.<\/p>\n\n

Take Q = mc\u0394T. It says the heat you must pour into something is set by three things and nothing else: how much of it there is, what it is made of, and how far you want its temperature to move. Change any one of those and the answer moves with it, in a way you can predict before you touch the apparatus.<\/p>\n\n

That is the part most formula sheets throw away. They give you the equation and leave out what each letter is<\/em> \u2014 which is precisely the information you need to use it.<\/p>\n\n

\"Physics<\/figure>\n\n

Every physics formula has this same anatomy: a subject, quantities, and units that must cancel correctly on both sides.<\/p>\n\n

Every Symbol Is a Quantity, and Every Quantity Has a Unit<\/h3>\n\n

The unit line at the bottom of that diagram is not decoration \u2014 it is a free correctness check. Kilograms times joules-per-kilogram-per-kelvin times kelvin leaves joules. The kilograms cancel, the kelvins cancel, and joules survive on both sides.<\/p>\n\n

If your units do not cancel down to the units of the answer, the formula is wrong or you have written it down wrong. No exceptions. This works because since 20 May 2019 the entire International System of Units<\/a> has been defined by seven fixed constants of nature, so every unit in every formula on this page traces back to the same seven numbers.<\/p>\n\n

The 10 Groups That Organise Every Physics Formula<\/h2>\n\n

Introductory physics is not one subject with a hundred formulas. It is ten small subjects with about ten formulas each \u2014 and that reframing is the single most useful thing on this page.<\/p>\n\n

Each group answers one question, and each has one signature formula that the rest of the group hangs off. Learn the signature and you have a hook to hang the others on.<\/p>\n\n

\"Map<\/figure>\n\n

The ten groups of physics formulas and the signature equation of each.<\/p>\n\n

\n\n\n\n\n
#<\/th>\nGroup<\/th>\nThe question it answers<\/th>\nSignature formula<\/th>\nCore SI units<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>Kinematics<\/strong><\/td>How is it moving?<\/td>v = u + at<\/td>m, s, m\/s, m\/s2<\/sup><\/td><\/tr>\n
2<\/td>Forces<\/strong><\/td>Why did the motion change?<\/td>F = ma<\/td>N, kg, m\/s2<\/sup><\/td><\/tr>\n
3<\/td>Work, energy & power<\/strong><\/td>What did it cost, and how fast?<\/td>KE = \u00bdmv2<\/sup><\/td>J, W<\/td><\/tr>\n
4<\/td>Momentum<\/strong><\/td>What survives a collision?<\/td>p = mv<\/td>kg\u00b7m\/s, N\u00b7s<\/td><\/tr>\n
5<\/td>Circular motion & gravitation<\/strong><\/td>What holds it on a curve?<\/td>F = GMm\/r2<\/sup><\/td>N, m, rad\/s<\/td><\/tr>\n
6<\/td>Fluids<\/strong><\/td>Will it float, and how hard does it push?<\/td>P = F\/A<\/td>Pa, kg\/m3<\/sup><\/td><\/tr>\n
7<\/td>Thermodynamics<\/strong><\/td>Where did the heat go?<\/td>Q = mc\u0394T<\/td>J, K, Pa<\/td><\/tr>\n
8<\/td>Waves, sound & optics<\/strong><\/td>How does it travel and repeat?<\/td>v = f\u03bb<\/td>Hz, m, m\/s<\/td><\/tr>\n
9<\/td>Electricity & magnetism<\/strong><\/td>What is charge doing?<\/td>V = IR<\/td>V, A, \u03a9, T<\/td><\/tr>\n
10<\/td>Modern physics<\/strong><\/td>What happens when it is very fast or very small?<\/td>E = mc2<\/sup><\/td>J, eV, Hz<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n

Everything below is grouped in that order. If you would rather put numbers in than read equations, every formula here also has a matching tool in our library of 97 physics calculators<\/a>, which solves each one for any variable you like.<\/p>\n\n

Mechanics Formulas: Motion, Forces, Energy and Momentum<\/h2>\n\n

Mechanics is roughly half of any introductory course, and groups 1 to 5 all live here. Start with motion described, then move to motion explained.<\/p>\n\n

Kinematics: Constant Acceleration (SUVAT)<\/h3>\n\n

These five formulas describe any object whose acceleration does not change. They are not five separate facts \u2014 they are one fact viewed from five angles, which is why you can always get from any three known quantities to the other two.<\/p>\n\n

v = u + at<\/div>\n\n
\n\n\n\n\n
Formula<\/th>\nGives you<\/th>\nUse it when<\/th>\nCalculator<\/th>\n<\/tr>\n<\/thead>\n
v = u + at<\/td>Final velocity<\/td>You know the time, not the distance<\/td>SUVAT<\/a><\/td><\/tr>\n
s = ut + \u00bdat2<\/sup><\/td>Displacement<\/td>You know the time and the start speed<\/td>SUVAT<\/a><\/td><\/tr>\n
s = \u00bd(u + v)t<\/td>Displacement<\/td>You know both speeds, not the acceleration<\/td>SUVAT<\/a><\/td><\/tr>\n
v2<\/sup> = u2<\/sup> + 2as<\/td>Final velocity<\/td>Time is not mentioned<\/strong> \u2014 the most useful one<\/td>SUVAT<\/a><\/td><\/tr>\n
s = vt \u2212 \u00bdat2<\/sup><\/td>Displacement<\/td>You know the end speed, not the start<\/td>SUVAT<\/a><\/td><\/tr>\n
vav<\/sub> = \u0394s \/ \u0394t<\/td>Average velocity<\/td>Acceleration is not constant<\/td>Velocity<\/a><\/td><\/tr>\n
a = \u0394v \/ \u0394t<\/td>Average acceleration<\/td>Acceleration is not constant<\/td>Acceleration<\/a><\/td><\/tr>\n
R = v0<\/sub>2<\/sup> sin(2\u03b8) \/ g<\/td>Projectile range<\/td>Level ground, no air resistance<\/td>Projectile Motion<\/a><\/td><\/tr>\n
H = v0<\/sub>2<\/sup> sin2<\/sup>\u03b8 \/ (2g)<\/td>Projectile peak height<\/td>Level ground, no air resistance<\/td>Projectile Motion<\/a><\/td><\/tr>\n
T = 2v0<\/sub> sin\u03b8 \/ g<\/td>Projectile flight time<\/td>Level ground, no air resistance<\/td>Projectile Motion<\/a><\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n