Find the magnitude of the free-fall acceleration at the orbit of the Moon (a distance of 60RE from the center of the Earth with the radius of RE). Use the gravitational acceleration on the surface of the Earth is 9.8m/s2.

The magnitude of the free-fall acceleration at the orbit of the Moon is (, where ).

Explanation:

According to the Newton's Law of Gravitation, free fall acceleration (), in meters per square second, is directly proportional to the mass of the Earth (), in kilograms, and inversely proportional to the distance from the center of the Earth (), in meters:

(1)

Where:

- Gravitational constant, in cubic meters per kilogram-square second.

- Mass of the Earth, in kilograms.

- Distance from the center of the Earth, in meters.

If we know that , and , then the free-fall acceleration at the orbit of the Moon is:

sleep paralysis is a parasomnia, events associated with sleep.

sleep paralysis happens when you are in the middle of waking up or falling asleep. it is the feeling of being conscious but unable to move. it definitely involves hallucinations.

i had a friend that had sleep paralysis and he told me a story one time where he was laying in bed and he couldn't move his body no matter how hard he tried and there was someone standing in the corner of his room coming towards him. he couldn't move and you can't "wake up" because you are already conscious. sometimes sleep paralysis can be triggered by frequent waking up during the night based off of multiple trips to the bathroom, or if you had ever been abused, sleep paralysis can start happening from things like that.