# InertiaEnglish: Inertia

Inertia is the resistance of the object to any change in its motion, including a change in direction. An object will stay still or keep moving at the same speed and in a straight line, unless it is acted upon by an external unbalanced force.

For example, a rubber ball will not start bouncing around unless someone picks it up and throws it. Basically, if an object is not moving, it will not start moving unless something else acts upon it. The same idea can be applied to motion: an object in motion will stay in motion unless some outside, opposing force acts upon it. Inertia is also called Sir Isaac Newton's First Law of Motion. The First Law of Motion says that:

Every body perseveres in its state of being at rest or of moving uniformly straight ahead, except insofar as it is compelled to change its state by forces impressed. [Cohen & Whitman 1999 translation]

This basically means:

Every object stays at rest or stays moving at the same speed unless something makes it change.

Johannes Kepler gave inertia it's name in Epitome Astronomiae Copernicanae (published in three parts from 1617–1621)

Albert Einstein developed the idea of Special Relativity based on Galileo's statement that it is impossible to tell the difference between a moving object and a stationary one without some outside reference to compare it against.

• related pages

## Related pages

Other Languages
አማርኛ: ግዑዝነት
العربية: قصور ذاتي
asturianu: Inercia
azərbaycanca: Ətalət
বাংলা: জড়তা
беларуская: Інерцыя
български: Инертност
bosanski: Inercija
català: Inèrcia
čeština: Setrvačnost
Cymraeg: Inertia
dansk: Inerti
Deutsch: Trägheit
eesti: Inerts
Ελληνικά: Αδράνεια
English: Inertia
español: Inercia
Esperanto: Inercio
euskara: Inertzia
فارسی: لختی
français: Inertie
Gaeilge: Táimhe
한국어: 관성
հայերեն: Իներցիա
हिन्दी: जड़त्व
hrvatski: Tromost
Bahasa Indonesia: Inersia
íslenska: Tregða
italiano: Inerzia
עברית: התמד
ಕನ್ನಡ: ಜಡತ್ವ
ქართული: ინერცია
қазақша: Инерция
Kiswahili: Inesha
Kreyòl ayisyen: Inèsi
Latina: Inertia
latviešu: Inerce
македонски: Инерција
മലയാളം: ജഡത്വം
Bahasa Melayu: Inersia
Nederlands: Traagheid
नेपाली: इनर्सिया

norsk: Treghet
norsk nynorsk: Tregleik
Novial: Inertia
occitan: Inercia
ਪੰਜਾਬੀ: ਇਨਰਸ਼ੀਆ
português: Inércia
русский: Инерция
shqip: Inercia
slovenčina: Zotrvačnosť
slovenščina: Vztrajnost
کوردی: ئینێرشیا
српски / srpski: Инерција
srpskohrvatski / српскохрватски: Tromost
suomi: Hitaus
svenska: Tröghet
Tagalog: Tigal
தமிழ்: நிலைமம்
Türkçe: Eylemsizlik
українська: Інерція
Tiếng Việt: Quán tính
Winaray: Anduroy