Ahorizontal force of 90.0 n is required to push a 75.0 kg along a horizontal surface at a constant speed. what is the magnitude of the force of friction (90.0n)

== You're pushing the load straight along the horizontal surface at a constant speed.

== The speed and direction of the load are not changing, so there is no acceleration.

== From Newton's 2nd law of motion, we know that  F = m A .  Since A=0, F must also be zero.  That means NO NET FORCE is acting on the load.

== But how can that be ? You're pushing it with 90 N !

== The NET force is zero.  So something else must be pushing the box, also with 90 N of force, exactly opposite to YOUR force, and they add up to zero.

== THERE's your force of friction !

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.