What is the SI unit of force?
AnswerNewton
Force is measured in newtons, named after Isaac Newton.
Science · Facts & stats
Force facts & stats
7 fact-checked facts about force in physics, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
According to Newton's third law, every action has...
AnswerAn equal and opposite reaction
Newton's third law says forces come in pairs: equal in size and opposite in direction.
Going deeper
Newton's second law is usually written as which equation?
AnswerF = ma
Force equals mass times acceleration.
What is the upward force a fluid exerts on an object in it called?
AnswerBuoyancy
Buoyancy equals the weight of fluid displaced, as described by Archimedes' principle.
What is the turning effect of a force called?
AnswerTorque (moment)
Torque is force multiplied by the perpendicular distance from the pivot.
Expert level
One newton is the force needed to give a 1 kg mass what acceleration?
Answer1 m/s²
By definition, 1 N = 1 kg·m/s², the force that accelerates 1 kg at 1 m/s².
Which fundamental force holds protons and neutrons together in an atomic nucleus?
AnswerThe strong nuclear force
The strong force binds nucleons together and overcomes the electric repulsion between protons.
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