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50 free Newton's Laws of Motion trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This Newton's laws of motion trivia quiz covers the three laws as a physics class teaches them and the history behind them. It starts with the laws themselves: the first law and inertia, the second law and the relationship between force, mass and acceleration, and the third law of action and reaction. Then it widens to the ideas the laws rest on, such as momentum, mass versus weight, friction, free fall, the newton as the SI unit of force, and why a rocket works in a vacuum. The easy questions ask which law explains why you lurch forward when a bus brakes and what the SI unit of force is called. The harder ones ask which book the laws first appeared in and in what year, who funded its printing, who coined the word 'inertia', which astronaut dropped a hammer and a feather on the Moon, and what Newton was doing at the Royal Mint. There is a short round on Isaac Newton himself: where he was born, when he was knighted and who he feuded with over calculus. If you want more, our physics and famous physicists quizzes continue the theme. Every answer was checked against the encyclopaedia entry for the law, the concept or the person before publishing, and the sentence that supports it is stored with each question.
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Q 01In which book did Isaac Newton first state his three laws of motion?
Philosophiæ Naturalis Principia Mathematica
Its title means 'Mathematical Principles of Natural Philosophy'; most people just call it the Principia.
Q 02In what year was the Principia originally published?
1687
Newton put out two more editions in his lifetime, a corrected one in 1713 and an improved one in 1726.
Q 03Newton's first law says a body's natural behaviour is to move how?
In a straight line at constant speed
That is the principle of inertia: left alone, a body keeps doing exactly what it is already doing.
Q 04According to the first law, what is needed to change a body's state of rest or uniform motion?
A force impressed upon it
Newton's wording was that a body continues in its state 'unless it is compelled to change that state by forces impressed upon it'.
Q 05Newton's second law says the change of motion is proportional to what?
The force impressed
And it happens along the straight line in which that force acts, which is why the law is written with vectors today.
Q 06In modern terms, the net force on a body equals its mass multiplied by what?
Its acceleration
That is the famous F = ma; equivalently, force is the rate at which the body's momentum changes.
Q 07When the net force on a body is zero, what is it said to be in?
Mechanical equilibrium
By the second law it does not accelerate, which covers both sitting still and coasting at constant velocity.
Q 08Newton's third law states that to every action there is always opposed what?
An equal reaction
The catch students miss is that the action and the reaction act on different bodies, so they never simply cancel.
Q 09Newton's third law is related to which more fundamental principle?
Conservation of momentum
Because paired forces are equal and opposite, they cancel when added, so the total momentum of the system stays constant.
Q 10Which thought experiment links a projectile's flight with orbital motion?
Newton's cannonball
Fire it fast enough and the ball falls away from a straight line at the same rate the Earth curves beneath it, so it never lands.
Q 11Linear momentum is the product of mass and what?
Velocity
The symbol p comes from the Latin pellere, meaning to push or drive.
Q 12In SI units, momentum is measured in what?
Kilogram metres per second
A 1 kg model plane flying north at 1 m/s has a momentum of 1 kg·m/s due north.
Q 13What is the SI unit of force?
The newton
It is a named derived unit; force is usually written with the symbol F.
Q 14One newton accelerates a mass of one kilogram at what rate?
Q 21In science, weight is a quantity associated with which pull on an object?
Gravitational force
Mass is how much matter there is; weight changes with the gravity around you, which is why astronauts float but do not lose mass.
Q 22Inertial mass measures an object's resistance to what?
Being accelerated by a force
Experiments have never found a difference between inertial mass and the gravitational mass that sets how hard gravity pulls.
Q 23A rocket engine produces thrust in accordance with which of Newton's laws?
The third law
One metre per second squared
In base units that is 1 kg·m/s², and the name was formally adopted by the CGPM in 1948.
Q 15In what year did the CGPM adopt the name 'newton' for the unit of force?
1948
The 9th General Conference on Weights and Measures did it by Resolution 7, two years after standardising the amount itself.
Q 16Because it has both magnitude and direction, force is what kind of quantity?
A vector
That is why two equal forces pulling in opposite directions add to nothing.
Q 17If a closed system feels no external forces, what happens to its total momentum?
It does not change
Momentum is conserved in every inertial frame, and the idea survives into relativity and quantum mechanics in modified form.
Q 18In which Italian city was Galileo born in 1564?
Pisa
His father Vincenzo was a lutenist and music theorist; the family moved to Florence when Galileo was ten.
Q 19Which scientist first introduced the term 'inertia'?
Johannes Kepler
He took it from the Latin for 'idleness' and used it only for resistance to movement; Galileo and Newton gave it its modern sense.
Q 20The word 'inertia' derives from a Latin word meaning what?
Idleness
Kepler assumed rest was the natural state of things, so inertia to him was a body's laziness about moving at all.
It throws hot gas backwards at high speed, and the reaction pushes the rocket forwards, so it works just as well in a vacuum.
Q 24Friction is the force resisting what?
Relative motion of surfaces in contact
Dry friction splits into static friction between surfaces that are not yet moving and kinetic friction once they slide.
Q 25Who discovered the classic laws of sliding friction in 1493, but never published them?
Leonardo da Vinci
They stayed hidden in his notebooks until Guillaume Amontons rediscovered them in 1699.
Q 26Who rediscovered the laws of dry friction in 1699, and now has them named after him?
Guillaume Amontons
Coulomb developed the theory further in 1785, and Euler was the first to separate static from kinetic friction.
Q 27Which astronaut dropped a hammer and a feather together on the Moon in 1971?
David Scott
With no air to slow the feather, both hit the lunar surface at the same moment, just as Galileo had argued.
Q 28In the Moon demonstration, what happened to the hammer and the feather?
They hit the surface at the same time
Free-fall acceleration does not depend on mass; on Earth only air resistance makes feathers drift.
Q 29According to a possibly apocryphal tale, Galileo dropped objects from which landmark?
The Leaning Tower of Pisa
The story dates the experiment to 1589–1592; the fall would have been too quick for him to learn much from it.
Q 30Which 1638 work by Galileo did Einstein cite in calling him the 'father of modern physics'?
Two New Sciences
He wrote it under house arrest; it deals mainly with the motion of bodies and the strength of materials.