Copper and aluminum are being considered for a high-voltage transmission line that must carry a current of 56.4 a. the resistance per unit length is to be 0.181 ω/km. the densities of copper and aluminum are 8960 and 2600 kg/m3, respectively. compute (a) the magnitude j of the current density and (b) the mass per unit length λ for a copper cable and (c) j and (d) λ for an aluminum cable.

a)

b)λ=0.83 kg/m

c)

d) λ=0.39 kg/m

Explanation:

Given that

I= 56.4 A

R= 0.181 Ω/km

Copper  :

d=8960 kg/m³

Aluminium :

d=2600 kg/m³

We know that

E= V/L

V= I R

J= E/ρ

For copper:

Mass per unit length λ

λ=0.83 kg/m

For  aluminum :

Mass per unit length λ

λ=0.39 kg/m

coil wire, increase current, put iron inside the coil

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.