If an object is not moving, it will not start moving by itself. If an object is moving, it will not stop or change direction unless something pushes it.

http://www.grc.nasa.gov/WWW/K-12/UEET/StudentSite/dynamicsofflight.html#lawofmotion



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This law is often called "The Law of Inertia" see animation examples on http://teachertech.rice.edu/Participants/louviere/Newton/law1.html


"The coin and the card on top of the cup is at rest. When I flick the card with my hand it goes away but the coin just falls Into the cup. I have no idea why the coin fell into the cup (maybe it is heaviness). The stronger I force the card to move the faster it goes. When the card hits the table it becomes slower and comes to rest again, and the coin that fell into the cup also comes to rest. Now everything is still."






Demystify Newton's first law of motion with none other than NASA -- the National Aeronautics and Space Administration. The United States government's most infamous agency and powerhouse of space exploration teaches you the law of inertia… Newton's first law of motion.



This NASA video segment from "Flight Testing Newton's Laws" explores how Newton's first law of motion applies to aerospace. An instructor at NASA's National Test Pilot School defines the law of inertia and then explains how the seatbelt in a jet provides an outside force to stop the inertia of the pilot. The instructor also discusses inertia experienced by humans while riding in the test vehicles for space travel.