Which simple machine is a ramp?
AnswerInclined plane
A ramp is an inclined plane: it lets you raise a load with less force over a longer distance.
Science · Facts & stats
Engineer facts & stats
7 fact-checked facts about engineering, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What is the SI unit of force?
AnswerNewton
Force is measured in newtons; one newton accelerates a 1 kg mass at 1 metre per second squared.
Going deeper
Why are triangles so common in bridge trusses?
AnswerA triangle cannot change shape without changing a side length
A triangle is rigid: its angles are fixed by its side lengths, so a truss of triangles resists deforming.
Which principle says a submerged object is pushed up by a force equal to the weight of fluid it displaces?
AnswerArchimedes' principle
Archimedes' principle explains buoyancy, which is why a steel ship can float.
What is usually embedded in concrete to help it resist being pulled apart?
AnswerSteel reinforcing bars
Plain concrete cracks easily when stretched, so steel rebar is added to carry those forces in reinforced concrete.
Expert level
Hooke's law says the force needed to stretch a spring is proportional to what?
AnswerThe distance it is stretched
Within its elastic limit, a spring's force grows in direct proportion to its extension: F = kx.
What material property does Young's modulus measure?
AnswerStiffness under stretching or compressing
Young's modulus is stress divided by strain in the elastic range, so a higher value means a stiffer material.
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