A .5kg book sits on top of a student's desk which is 9m high. How much gravitational potential energy does the book have as it sits on the desk?

441J

Explanation:

Given parameters:

Mass of book  = 5kg

Height  = 9m

Unknown:

Gravitational potential energy  = ?

Solution:

The gravitational potential energy of a body is the energy due to the position of the body.

 It is given as:

   Gravitational potential energy = mass x acceleration due to gravity x height

Gravitational potential energy  = 5 x 9.8 x 9  = 441J

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.