Mission CG7 Gravitational Field Strength

Getting your Trinity Audio player ready...

Hold down the T key for 3 seconds to activate the audio accessibility mode, at which point you can click the K key to pause and resume audio. Useful for the Check Your Understanding and See Answers.

Four different planets with different masses are depicted below. A location about the planet is also indicated. Rank the four locations in increasing order of their acceleration of gravity value, beginning with the lowest. Enter your four answers in increasing order with no spaces or commas between letters.

The acceleration of gravity (g) is the acceleration an object experiences when the only force acting upon it is gravity. According to Newton's universal gravitation law, its value can be predicted by the following equation:

g = G • M_planet / d²

where M_planet represents the planet's mass and d represents the distance that the object is from the planet's center.

Click the button below to play an audio file.

This is a very difficult question which explores the relationship between the acceleration of gravity, the distance from a planet's center and the mass of the planet. As demonstrated by the equation in the Formula Frenzy section, the acceleration of gravity is dependent upon the M_planet / d² ratio. You will need to find this ratio for locations A and B. Take your time and write down the results. If one of the locations is a distance R above the planet's surface, then the separation distance (d) is 2•R. Once you have found this important ratio for both locations, you will be ready to answer the question.