Physics guides
Calculate motion, force, energy, momentum, and other physics formulas with detailed explanations.
19 guides · each with a free step-by-step calculator
Physics Calculator: Solve Motion, Force & Energy Problems Step by Step
Why does a car at 100 km/h need about four times the braking distance of one at 50 km/h? Because its kinetic energy grows with the square of its speed. In this guide you'll learn the core formulas of motion, force and energy, and a simple routine for solving physics problems without getting lost in the units.
Force Formula: How to Calculate Force (F = ma)
Why does a shopping cart feel so much heavier to push once it's full? The answer is Newton's second law, F = m × a — one short formula that predicts the push or pull behind every moving object, from a rolling ball to a rocket.
Kinetic Energy Formula: KE = ½mv² Explained
Why is a fast-moving car so much more dangerous than a slow one, even at the same weight? The energy hidden in motion, kinetic energy, grows far faster than speed itself. This guide shows you exactly how to calculate it.
Gravitational Potential Energy Formula (PE = mgh)
Why does a book falling off a high shelf hurt more than one falling off a low table? The height stores energy before anything even moves, gravitational potential energy, and PE = mgh tells you exactly how much.
Ohm's Law Formula: How to Calculate Voltage
Why does a thin wire heat up while a thick one stays cool, carrying the same current? The answer is resistance, and Ohm's Law, V = I × R, is the one formula that ties voltage, current, and resistance together.
How to Calculate Power (P = V × I)
Why does a kettle boil water in minutes while a phone charger barely warms up, even on the same wall socket? The answer is power, P = V × I, which shows how fast a device turns electricity into heat, light, or motion.
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Velocity Formula: How to Calculate v = d/t
How fast is 'fast,' exactly? Velocity turns a vague feeling of speed into a precise number, distance divided by time, the same idea a sprinter's coach and a physics exam both rely on.
How to Calculate Speed (Distance ÷ Time)
How long will a 150 km drive really take? Speed turns distance and time into one easy number to compare, whether you're planning a road trip or checking a runner's pace.
Acceleration Formula: a = (v - u) / t Explained
What actually makes one car feel 'quick' off the line? It's not top speed, it's acceleration, how fast the speed itself is climbing. The formula a = (v − u) ÷ t turns that feeling into a number.
Momentum Formula: How to Calculate p = mv
Why is it so much harder to stop a loaded truck than an empty one moving at the same speed? Momentum combines mass and velocity into one number that measures exactly how hard something is to stop.
Density Formula: How to Calculate ρ = m/V
Why does a small bar of lead feel far heavier than a foam block the same size? It comes down to density, how tightly mass is packed into a given space, and ρ = m ÷ V tells you exactly how to measure it.
Work Done Formula: How to Calculate W = Fd
Can you do 'work' and still get nowhere? In physics, yes — pushing a wall that doesn't budge counts as zero work, no matter how tired you get. W = F × d shows exactly why movement is the whole point.
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Pressure Formula: How to Calculate P = F/A
Why does a sharp knife slice through a tomato with almost no effort, while a blunt one squashes it? The same force, spread over a much smaller area, creates far higher pressure, and P = F ÷ A explains exactly why.
Torque Formula: How to Calculate τ = F × r
Why does a longer wrench make a stubborn bolt so much easier to turn? It's not extra strength, it's torque, the turning effect of a force, and τ = F × r shows exactly how distance from the pivot multiplies your effort.
Free Fall Distance Formula: d = ½gt²
How far does a dropped phone actually fall in the two seconds before it hits the ground? Gravity accelerates everything at the same steady rate, and d = ½gt² tells you exactly how far that adds up to.
Projectile Range Formula: R = v²sin(2θ)/g
What angle sends a soccer ball the furthest, straight and flat or high and arcing? Neither, it turns out. The sweet spot is 45 degrees, and R = v²sin(2θ)/g explains exactly why.
Wave Speed Formula: How to Calculate v = fλ
Why does a low, booming bass note and a high whistle travel through the same room at exactly the same speed? Sound waves trade frequency for wavelength, and v = f × λ shows how the two balance out.
Ideal Gas Law: How to Find Volume (V = nRT/P)
Why does a sealed bag of chips puff up on a flight? Gas volume depends on pressure and temperature, and the ideal gas law, V = nRT/P, is the formula behind exactly that kind of everyday surprise.
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Coulomb's Law: How to Calculate Electric Force
Why does a balloon rubbed on your hair stick to a wall? Static electricity is a real force between charges, and Coulomb's Law, F = kq₁q₂/r², shows exactly how strong that invisible push or pull is.
