An asteroid exerts a 360-n gravitational force on a nearby spacecraft. if the spacecraft moves to a position three times as far from the center of the asteroid, the force will be

zero
40n
120n
360n
1080n

40 N

Explanation:

The gravitational force between the asteroid and the spaceship is given by:

where

is the gravitational constant

is the mass of the asteroid

is the mass of the spaceship

is the distance between the asteroid and the spaceship

The initial force is equal to:

Later, the spaceship moves to a position 3 times as far from the center of the asteroid, so R' = 3R. Therefore, the new force will be

so, the force is decreased by a factor 9. Since the initial force was F=360 N, the new force will be

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