Universal Gravitation questions

**jshaner858** · Oct3-05, 11:52 PM

1) if something is 5 earth radii above the earth's surface and you know its mass, how would you figure out force of gravity on it?

2)and given the radius and mass of a planet how would you be able to figure out the acceleration due to gravity on it?

**Grogs** · Oct4-05, 12:23 AM

Originally Posted by jshaner858

1) if something is 5 earth radii above the earth's surface and you know its mass, how would you figure out force of gravity on it?

2)and given the radius and mass of a planet how would you be able to figure out the acceleration due to gravity on it?

$LaTeX Code: <BR>a_{grav} = \\frac{GM}{r^2}<BR>$

where G is the gravitational constant, M is the mass of the planet, and r is the distance from the center of the planet.

**jshaner858** · Oct4-05, 12:38 AM

that won't work for the first question...the object is a spaceship and there is nowhere in that equation to plug in its mass...

**jshaner858** · Oct4-05, 12:41 AM

nevermind i figured it out myself...thanks