🍎 Newton's Second Law Calculator (F = ma)
Apply F = ma: enter any two of force, mass and acceleration and get the third.
Force F
98 N
Newton’s second law: F = m·a (force = mass × acceleration). For weight, use a = g. 🔒 Computed in your browser.
How the newton's second law calculator (f = ma) works
Newton’s second law states that the net force on an object equals its mass times its acceleration: F = ma. Enter any two of the three and the tool solves for the remaining one. For weight, set a to g (9.8 m/s²). More precisely, force equals the rate of change of momentum, F = Δp/Δt, which reduces to F = ma whenever the mass is constant.
The foundation of dynamics. Force in newtons, mass in kilograms, acceleration in m/s². To find weight, use F = mg with g ≈ 9.8 m/s².
Frequently asked questions
What is Newton’s second law?
The net force on an object equals mass times acceleration: F = ma. A larger force gives more acceleration; a larger mass gives less for the same force.
How do I find acceleration from force and mass?
Rearrange to a = F/m. A 50 N force on a 10 kg object gives 5 m/s². Enter force and mass to get acceleration.
How do I calculate weight?
Weight is the gravitational force: W = mg, with g ≈ 9.8 m/s². A 10 kg mass weighs about 98 N. Use a = g in this tool.
What units does F = ma use?
Force in newtons (N), mass in kilograms (kg), acceleration in metres per second squared (m/s²). 1 N = 1 kg·m/s².
Is F the net force?
Yes, F is the resultant (net) of all forces acting. If forces oppose, subtract them first to get the net force before applying F = ma.
Worked example: pushing a trolley
A 30 N net force on a 6 kg trolley gives a = F/m = 30/6 = 5 m/s². If two equal 30 N forces oppose each other, the net force is zero and there is no acceleration.
What is the difference between mass and weight?
Mass (in kg) is the amount of matter and is the same everywhere; weight (in newtons) is the gravitational force on it, W = mg, and changes with gravity. F = ma uses mass, not weight.
What is Newton’s first law?
An object stays at rest, or moves at constant velocity, unless acted on by a net force, the special case of F = ma when F = 0, so a = 0. It captures inertia and sets the stage for the second law.
Why write F = Δp/Δt instead of F = ma?
The momentum form F = Δp/Δt is more general: it still holds when the mass changes, such as a rocket burning fuel. It reduces to F = ma only when the mass is constant, which covers most everyday problems.