Inertia - Inertia and Newton's First Law of Motion
Quatr.us answers questions
Upgrade /Log in
Options /Log out
Print
About
Africa
Egypt
Mesopotamia
Early Europe
Greece
Rome
China
India
Central Asia
Medieval
Islamic Empire
Native Americans
S./Central America
American History
Biology
Chemistry
Geology
Math
Physics
Weather
Food
Judaism
Christianity
Home

Inertia

Pushing a bus

A law of physics states that "an object at rest tends to remain at rest, and an object in motion tends to remain in motion." Scientists call these tendencies inertia. Inertia is a way of measuring how hard it is to change the momentum of an object, whether that's getting it to speed up or getting it to slow down. That depends on how much mass the object has. Big heavy things (things with a lot of mass) have more inertia than light things. You have to push a bus harder than a scooter to get it to move.

If something has a lot of mass, it's also hard to get it to stop moving. If the bus was moving fast, you'd need good brakes to get it to stop. Because the bus has more mass than the scooter, it would be a lot harder to stop the bus. That's also inertia - inertia's a way of measuring how hard it is to get something to stop moving, too.

Bibliography and further reading about physics:

Stars
Space
Physics
Quatr.us home


Professor Carr

Karen Eva Carr, PhD.
Assoc. Professor Emerita, History
Portland State University

Professor Carr holds a B.A. with high honors from Cornell University in classics and archaeology, and her M.A. and PhD. from the University of Michigan in Classical Art and Archaeology. She has excavated in Scotland, Cyprus, Greece, Israel, and Tunisia, and she has been teaching history to university students for a very long time.

Professor Carr's PSU page

Help support Quatr.us!

Quatr.us (formerly "History for Kids") is entirely supported by your generous donations and by our sponsors. Most donors give about $10. Can you give $10 today to keep this site running? Or give $50 to sponsor a page?

With Mother's Day coming up, remember the Mother Goddesses: Mut, Isis, Gaia, Hera, Demeter, Parvati, and the Corn Mother. And honor powerful mothers: Ankhesenpepi II, Agrippina, Wu Chao, Blanche of Castile, Catherine de' Medici, Hamida Banu and Nur Jahan, Nurbanu Sultan, Sofia Baffo, Xiaozhuang, Anne of Austria. A great Mother's Day story: Kleobis and Biton.