When the rocket engine burns fuel m so that it leaves the rocket with speed u, it carries momentum in one direction (to the left in this diagram). To conserve momentum, the rocket must carry momentum -- or gain additional momentum -- in the opposite direction (to the right in this diagram).
Conservation of momentum requires that
Sidebar or footnote:
Voyager 2 Approaching Uranus:
This artist's conception shows the final approach of the unmanned spacecraft Voyager 2 toward the planet Uranus on January 24, 1986. Voyager 2 discovered four new rings and ten new moons around Uranus. An interesting "sidebar" is that these rings of Uranus were discovered by a team of Astronomers led by Robert Millis, an Eastern Physics graduate. Dr Millis is now director of the Lowell Observoratory in Flagstaff AZ.
A Special Case Summary Return to ToC, Work and Energy (c) 2002, Doug Davis; all rights reserved