洗涮

//那天不知道　多麼堅固壯麗的
原來是個沙造的堡壘//

喬靖夫

相忘

厲曼婷︰「浪滔滔  人渺渺」
//昨日非今日該忘//

asthma drug

//Farmers have been known to use the drug in livestock feed to promote leaner meat - and higher prices.//

scmp.com

逢藥三分毒

Artane (oral) decreases production of saliva, dry mouth may occur. Severe dry mouth can also lead to increased levels of tooth decay.

visible light

紅橙黃綠青藍紫，嚴格來是錯誤的光譜劃分。
紅橙黃綠藍靛紫，是科學家嚴密的區分。

靛︰indigo

spectrum of visible light
wavelength is between 400nm to 700nm

Looking up into a dictionary

Moustache is the hair growing on the human upper lip.

Shudder: shiver

Hum: to express by making a vocal sound with the lips pressed together

Wrestle: to combat an opposing tendency or force

Tawny: of a warm sandy color

Flutter: to flap the wings rapidly

Peck: a quick light kiss

Tantrum: a fit of bad temper

Tyke: a small child

Chortle: to laugh or chuckle especially when amused or pleased

Chuckle: to laugh inwardly or quietly

Back out: to withdraw

Peculiar: characteristic of only one person, group, or thing

Jerk: to give a quick suddenly arrested push, pull, or twist to

Tabby: a domestic cat with a striped and mottled coat

Cloak: a loose outer garment

Huddle: a close-packed group

Weirdo: a person who is extraordinarily strange or eccentric

Eccentric: deviating from conventional or accepted usage or conduct

Enrage: be angry

Emerald: a rich green variety of beryl prized as a gemstone

Swoop: to move with a sweep

Clutch: to grasp or hold with or as if with the hand or claws usually strongly, tightly, or suddenly

Grunt: to utter a grunt

Utter: to send forth as a sound

Stumble: to walk unsteadily or clumsily

Squeaky: to utter or make a short shrill cry or noise

Shrill: scream

Set off: to set in motion

Stern: expressive of severe displeasure

Grin: smile

Downpour: a heavy rain

Mumble: to utter with a low inarticulate voice

Creep: to go very slowly

Peer: to look narrowly or curiously

Yawn: to open the mouth wide and take a deep breath usually as an involuntary reaction to fatigue or boredom

Quiver: to shake or move with a slight trembling motion

Slam: to shut forcibly and noisily

Twitch: to move jerkily

Tuck: to push in the loose end of so as to hold tightly

Crooked: not straight

Rummage: to make a thorough search or investigation

Mutter: to utter sounds or words indistinctly or with a low voice and with the lips partly closed

Feast: an elaborate and usually abundant meal often accompanied by a ceremony or entertainment

Sniff: to take air into the nose in short audible breaths

Flock: a group of animals (such as birds or sheep) assembled

Swap: to take turns in telling

Sherbet: a cold drink of sweetened and diluted fruit juice

Exasperate: to cause irritation or annoyance to

Blush: to become red in the face especially from shame, modesty, or confusion

Earmuffs: one of a pair of ear coverings connected by a flexible band and worn as protection against cold or noises

Falter: to speak brokenly or weakly

Astounding: causing astonishment or amazement

Grudgingly: unwillingly, reluctantly

Tangle: a matted, twisted mass

Beard: the hair that grows on a man's face often excluding the mustache

Swarm: a large number of animate or inanimate things massed together and usually in motion

Bolt: a lightning stroke

Whisker: a hair of the beard

Howl: to emit a loud sustained doleful sound characteristic of members of the dog family

Sob: to cry or weep with convulsive catching of the breath

Gingerly: very cautious or careful

Furious: exhibiting or goaded by anger

Breeze: a light gentle wind

Dictionary:
https://www.merriam-webster.com

earth-cloud capacitor

試想地面與地面上方800米處的雲層是平行極板的電容。 如果雲層的面積為1.0平方公里= 1.0×106平方米，那麼電容是多少？ 如果電場強度大於3.0×106 N / C會導致閃電，那麼雨雲可以承受的最大電荷是多少？

Consider the Earth and a cloud layer 800 meters above the Earth to be the plates of a parallel-plate capacitor. If the cloud layer has an area of 1.0 km² = 1.0×10⁶ m², what is the capacitance? If an electric field strength greater than 3.0×106 N/C causes the air to break down and conduct charge (lightning), what is the maximum charge the cloud can hold?

The definition of capacitance is given by this equation: capacitance C, measured in farads, equals charge Q, measured in coulombs, divided by voltage V, measured in volts.

C = Q/ΔV

V = P / I (unit: J*s^-1A^-1)

(Unit: F = A*s / J*s^-1A^-1 = A²s²J^-1)

Force, F’ = ma

(Unit: kg*m*s^-2)

J = N*1 meter

(Unit: kg*m²*s^-2)

a = (vf - vi) / (tf - ti)

vf: final velocity

vi: initial velocity

tf: final time

ti: initial time

(Unit: F = A²s²J^-1 = A²s²kg^-1m^-2s² = A²s⁴kg^-1m^-2)

Farad (F) is the unit of capacitance. The farad measures how much electric charge is accumulated on the capacitor. 1 farad is the capacitance of a capacitor that has charge of 1 coulomb when applied voltage drop of 1 volt.

Coulomb (C, A*s) is the SI unit of electric charge, equal to the quantity of electricity conveyed (傳送) in one second by a current of one ampere.

Voltage can also be stated as electric potential along a wire when an electric current of one ampere dissipates (消散) one watt (W) of power (W = J/s).

Ampere (A) represents a flow of one coulomb of electricity per second. A flow of one ampere is produced in a resistance of one ohm by a potential difference of one volt.

Joule (J) is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter.

Newton (N), the absolute unit of force in the International System of Units (SI units). It is defined as that force necessary to provide a mass of one kilogram with an acceleration of one meter per second per second.

The capacitance depends on the area of the plates, A, the size of the gap, d, and the insulator between the plates. We will assume that the insulator is air here:

Ɛ₀ = 1/(4πk)

where k is the Coulomb constant.

(Unit: C²/Nm²)

C = Ɛ₀ A / d

where Ɛ₀ is a constant called the permittivity of free space.

(Unit: C²N^-1m^-2_*m²m^-1 = C²N^-1m^-1)

Electric field strength, E = V/d (Unit: N/C = V/m)

Q = CΔV = CEd

(Unit: C²N^-1m^-1NC^-1m = C)

N/C = kg*m*s^-2*A^-1s^-1 = kg*m*s^-3A^-1
Newton Per Coulomb (N/C) has a dimension of MLT^-3I^-1 where M is mass, L is length, T is time, and I is electric current.

V/m = J*s^-1A^-1m^-1 = kg*m²*s^-2*s^-1A^-1m^-1 = kg*m*s^-3A^-1

Source:

hep.physics.wayne.edu

www.britannica.com

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