NASA Logo - Web Link to NASA.gov

+ Text Only Site
+ Non-Flash Version
+ Contact Glenn

Go
ABOUT NASA NEWS AND EVENTS MULTIMEDIA MISSIONS MyNASA WORK FOR NASA
 

NASA Logo
  About Rockets
 


Start Your Journey

  Rocket Research 101
  Rocket Research 102
  Rocket Research 103

  Educator Section
  Rocket Safety
  The Simulators
  Install 3D Simulator
  Home


START YOUR JOURNEY - LAWS OF MOTION

 

Newton’s Laws of Motion Challenge

You Chose :

1. The Law of Inertia:

“An object at rest tends to stay at rest and an object in motion tends to stay in motion.”

This choice is not the right one for the example.

However, it still applies to rocket flight! It’s easiest to see how this Law works once the rocket gets above the Earth’s atmosphere (to avoid air resistance).

Because there is very little friction in orbit, when a satellite is “in motion” it will stay “in motion,” orbiting the Earth continually just as Newton predicted…until something (a force, say from a rocket motor) comes along to change that condition.

There are some residual air molecules where the satellites orbit. So they do encounter very slight air resistance, which can eventually slow them down (it takes many years). We call this “orbital decay.” Rocket boosters on a satellite can correct this decay from time to time.

The law is also valid on Earth. However, on the surface of the planet, air resistance is present and slows a moving object. To counter air resistance, you need to apply a continuous forward force. This is why automobiles must constantly run their engines. Your car has additional friction from the wheels, wheel bearings, and from the road. Therefore, the sole purpose of running the engine continuously is to overcome all the different friction sources. Otherwise, a small push would keep your car going forever. (Hills and valleys present special situations…but that’s another story.)

 

>>Try Again - Back to the Acceleration page

Any comments, concerns, or questions should be addressed to:    

Developer: David Mazza    
Responsible NASA Official: Jo Ann Charleston    

 
TP Logo

 

     First Gov Image


+ Inspector General Hotline
+ Equal Employment Opportunity Data Posted Pursuant to the No Fear Act
+ Budgets, Strategic Plans and Accountability Reports
+ Freedom of Information Act
+ The President's Management Agenda
+ NASA Privacy Statement, Disclaimer,
and Accessibility Certification

 

   
Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: May 13 2021

+ Contact Glenn