Owner, this is really too much. You should ask what you don’t know and what you need to know. . . I just listed some for you.
Hope to adopt!
Physical quantity (unit) Formula notes Deformation of formula
Speed ??V (m/S) v= S: distance/t: time
Gravity G (N ) G=mg m: Mass g: 9.8N/kg or 10N/kg
Density ρ (kg/m3) ρ=m/V m: Mass V: Volume
Resultant force F combined (N) has the same direction: F combined = F1 + F2
Opposite direction: F combined = F1—F2 When the direction is opposite, F1>F2
The buoyancy force F floats
(N) F float = G object - G view G view: the gravity of the object in the liquid
Buoyancy F float
(N) F float = G object this formula Applicable only
Objects float or suspend
Buoyancy F float
(N) F float = G row = m row g = ρ liquid g V row G row: The gravity of the liquid displaced
m row: the mass of the liquid displaced
ρ liquid: the density of the liquid
V row: the volume of the liquid displaced
p>
(i.e. the volume immersed in the liquid)
The equilibrium condition of the lever F1L1= F2L2 F1: power L1: power arm
F2: resistance L2: resistance arm
p>Fixed pulley F=G object
S=h F: The tension on the free end of the rope
G object: The gravity of the object
S : The distance the free end of the rope moves
h: The distance the object rises
Moving pulley F= (G object + G wheel)
S=2 h G Object: the gravity of the object
G wheel: the gravity of the moving pulley
Pulley set F= (G object + G wheel)
S=n h n: the force passing through the moving pulley rope Number of segments
Mechanical work W
(J) W=Fs F: force
s: distance moved in the direction of the force
Useful work W has
Total work W total W has = G object h
W total = Fs is applicable when the pulley block is placed vertically
Mechanical efficiency η= ×100%
Power P
(w) P=
W: work
t: time
Pressure p
(Pa) P=
F: Pressure
S: Forced area
Liquid pressure p
(Pa) P=ρgh ρ: density of liquid
h: depth (vertical distance from the liquid surface to the desired point
)
< p>Heat Q(J) Q=cm△t c: Specific heat capacity of the substance m: Mass
△t: Change value of temperature
Fuel combustion releases
The amount of heat Q (J) Q=mq m: mass
q: calorific value
Commonly used physical formulas and important knowledge points
< p>1. Physical formulaUnit) Formula notes Variation of formula
Series circuit
Current I (A) I=I1=I2=... The current is the same everywhere
p>
Series circuit
Voltage U (V) U=U1+U2+... The series circuit plays the role of voltage divider
Series circuit
Series circuit
p>Resistance R (Ω) R=R1+R2+……
Parallel circuit
Current I (A) I=I1+I2+…… The main circuit current is equal to each
Sum of branch currents (shunt)
Parallel circuit
Voltage U (V) U=U1=U2=……
Parallel circuit
Resistance R (Ω) = + +......
Ohm's law I=
Current and voltage in the circuit
Proportional and inversely proportional to resistance
Current definition formula I=
Q: Charge (Coulomb)
t: Time (S)
Electrical power W
(J) W=UIt=Pt U: Voltage I: Current
t: Time P: Electric power
Electrical power P=UI=I2R=U2/R U: voltage I: current
R: resistance
Electromagnetic wave speed and wave
The relationship between length and frequency C=λν C:
Physical quantity unit formula
Name symbol Name symbol
Mass m kilogram kg m=pv
< p>Temperature t degrees Celsius °CSpeed ??v meters/second m/s v=s/t
Density p kilogram/meter 3 kg/m3 p=m/v
Force (gravity) F Newton (cow) N G=mg
Pressure P Pascal (Pascal) Pa P=F/S
Work W Joule (Joule) J W= Fs
Power P watts (watts) w P=W/t
Current I amperes (amps) A I=U/R
Voltage U volts (volts ) V U=IR
Resistance R ohms (ohms) R=U/I
Electrical power W Joules (joules) J W=UIt
Electrical power P watts ( Watt) w P=W/t=UI
Heat Q Joule (joule) J Q=cm(t-t°)
Specific heat c joule/(kilogram °C) J/( kg°C)
The speed of light in vacuum is 3×108 meters/second
g 9.8 Newton/kg
The speed of sound in air at 15°C is 340 meters/second< /p>
Compilation of junior high school physics formulas
Mechanics part
1. Speed: V=S/t
2. Gravity: G=mg< /p>
3. Density: ρ=m/V
4. Pressure: p=F/S
5. Liquid pressure: p=ρgh
6. Buoyancy:
(1), Fbuoyancy=F'-F (pressure difference)
(2), Fbuoyancy=G-F (depending on gravity)
(3), F float = G (floating, suspended)
(4), Archimedes' principle: F float = G row = ρ liquid gV row
7. Lever balance conditions: F1 L1＝F2 L2
8. Ideal slope: F/G＝h/L
9. Ideal pulley: F=G/ n
10. Actual pulley: F=(G+G moving)/n (vertical direction)
11. Work: W=FS=Gh (lift the object high)
p>
12. Power: P=W/t=FV
13. The principle of work: W hand=W machine
14. Actual machinery: W total=W Yes + W extra
15. Mechanical efficiency: η＝W Yes/W total
16. Pulley block efficiency:
(1), η＝G/ nF (Vertical direction)
(2), η＝G/(G+G motion) (Vertical direction does not include friction)
(3), η＝f / nF (Horizontal direction )
Thermal part
1. Endothermic: Q absorb=Cm(t-t0)=CmΔt
2. Endothermic: Q release=Cm( t0-t)=CmΔt
3. Calorific value: q=Q/m
4. Efficiency of furnace and heat engine: η=Q effective utilization/Q fuel
5. Thermal balance equation: Q discharge = Q absorb
6. Thermodynamic temperature: T＝t+273K
Electrical part
1. Current intensity: I =Q power/t
2. Resistance: R=ρL/S
3. Ohm’s law: I=U/R
4. Joule’s law:
(1), Q=I2Rt universal formula)
(2), Q=UIt=Pt=UQ power=U2t/R (pure resistance formula)
5. Series circuit:
(1), I＝I1＝I2
(2), U＝U1＋U2
(3), R ＝R1＋R2
(4), U1/U2＝R1/R2 (pressure dividing formula)<
/p>
(5), P1/P2＝R1/R2
6. Parallel circuit:
(1), I＝I1＋I2
(2), U＝U1＝U2
(3), 1/R＝1/R1＋1/R2 [ R＝R1R2/(R1＋R2)]
(4), I1 /I2＝R2/R1 (shunt formula)
(5), P1/P2＝R2/R1
7 fixed value resistor:
(1) , I1/I2＝U1/U2
(2), P1/P2＝I12/I22
(3), P1/P2＝U12/U22
8 Electric power:
(1), W＝UIt＝Pt＝UQ (universal formula)
(2), W＝I2Rt＝U2t/R (pure resistance formula) )
9 Electric power:
(1), P＝W/t＝UI (universal formula)
(2), P＝I2R＝U2 /R (pure resistance formula)
Commonly used physical quantities
1. Speed ??of light: C=3×108m/s (in vacuum)
2. Speed ??of sound: V ＝340m/s (15℃)
3. Human ear distinguishes echo: ≥0.1s
4. Gravity acceleration: g＝9.8N/kg≈10N/kg< /p>
5. Standard atmospheric pressure value:
760 mm mercury column height = 1.01×105Pa
6. Density of water: ρ=1.0×103kg /m3
7. The freezing point of water: 0℃
8. The boiling point of water: 100℃
9. The specific heat capacity of water:
< p>C＝4.2×103J/(kg?℃)10. Element charge: e＝1.6×10-19C
11. Voltage of one dry cell: 1. 5V
12. Voltage of one lead-acid battery: 2V
13. Safety voltage for human body: ≤36V (not higher than 36V)
14 , Power circuit voltage: 380V
15. Household circuit voltage: 220V
16. Unit conversion:
(1), 1m/s=3. 6km/h
(2), 1g/cm3 =103kg/m3
(3), 1kw?h＝3.6×106J
Junior high school physics Formula compilation
Mechanics part
1. Speed: V=S/t
2. Gravity: G=mg
3. Density: ρ=m/V
4. Pressure: p=F/S
5. Liquid pressure: p=ρgh
6. Buoyancy: < /p>
(1), F float=F'-F (pressure difference)
(2), F float=G-F (depending on gravity)
( 3), F float = G (floating, suspended)
(4), Archimedes' principle: F float = G row = ρ liquid gV row
7. Lever balance Conditions: F1 L1＝F2 L2
8. Ideal slope: F/G＝h/L
9. Ideal pulley: F=G/n
10. Actual pulley: F=(G+G moving)/n (vertical direction)
11. Work: W=FS=Gh (lifting the object high)
12. Power : P＝W/t＝FV
13. Principle of work: W hand = W machine
14. Actual machinery: W total = W + W extra
< p>15. Mechanical efficiency: η=W / W total16. Pulley block efficiency:
(1), η=G/nF (vertical direction)
(2), η=G/(G+G motion) (friction is not included in the vertical direction)
(3), η=f / nF (horizontal direction)
Thermal part
1. Endothermic: Q absorption=Cm(t-t0)=CmΔt
2. Heat release: Q release=Cm(t0-t)=CmΔt
p>>3. Calorific value: q=Q/m
4. Efficiency of furnaces and heat engines: η=Q effective utilization/Q fuel
5. Heat balance equation: Q discharge=Q Suction
6. Thermodynamic temperature: T＝t＋273K
Electrical part
1. Current intensity: I＝Q power/t
2. Resistance: R=ρL/S
3. Ohm’s law: I=U/R
4. Joule’s law:
(1), Q =I2Rt universal formula)
(2), Q=UIt=Pt=UQ power=U2t/R (pure resistance formula)
5. Series circuit:
(1), I＝I1＝I2
(2), U＝U1＋U2
(3), R＝R1＋R2
(4) , U1/U2＝R1/R2 (voltage division formula)
(5), P1/P2＝R1/R2
6. Parallel circuit:
(1), I＝I1＋I2
(2), U＝U1＝U2
(3), 1/R＝1/R1＋1/R2 [ R＝R1R2/(R1＋R2 )]
(4), I1/I2＝R2/R1 (diversion formula)
(5), P1/P2＝R2/R1
7 Fixed value resistor:
(1), I1/I2＝U1/U2
(2), P1/P2＝I12/I22
(3) , P1/P2＝U12/U22
8 electrical power:
(1), W＝UIt＝Pt＝UQ (universal formula)
（ 2), W＝I2Rt＝U2t/R (pure resistance formula)
9 Electric power:
(1), P＝W/t＝UI (universal formula)
p>
(2), P=I2R=U2/R (pure resistance formula)
Commonly used physical quantities
1. Speed ??of light: C=3×108m/s (vacuum Medium)
2. Speed ??of sound: V=340m/s (15℃)
3. Human ear distinguishes echo: ≥0.1s
4. Gravity Acceleration: g＝9.8N/kg≈10N/kg
5. Standard atmospheric pressure value:
760 mm mercury column height = 1.01×105Pa
6. Density of water: ρ=1.0×103kg/m3
7. Freezing point of water: 0℃
8. Boiling point of water: 100℃
9. Specific heat capacity of water:
C＝4.2×103J/(kg?℃)
10. Element charge: e＝1.6×10-19C
11. Voltage of one dry cell: 1.5V
12. Voltage of one lead-acid battery: 2V
13. Safety voltage for human body: ≤36V (Not higher than 36V)
14. Power circuit voltage: 380V
15. Household circuit voltage: 220V
16. Unit conversion:
(1), 1m/s=3.6km/h
(2), 1g/cm3=10^3kg/m^3
Element No. 01 : Hydrogen [chemical symbol] H, pronounced "light"
Element No. 02: Helium [chemical symbol] He, pronounced "Hai"
Element No. 03: Lithium [Chemistry Symbol] Li, pronounced "里"
Element No. 04: Beryllium [chemical symbol] Be, pronounced "Pi"
Element No. 05: Boron [chemical symbol] B, Pronounced "Peng"
Element No. 06: Carbon [chemical symbol] C, pronounced "Carbon"
Element No. 07: Nitrogen [chemical symbol] N, pronounced "Lan"
Element No. 08: Oxygen [chemical symbol] O, pronounced "Yang"
Element No. 09: Fluorine [chemical symbol] F, pronounced "F"
Element 10: Neon
[Chemical symbol] Ne, pronounced "Na"
Element No. 11: Sodium [Chemical symbol] Na, pronounced "Na"
Element No. 12: Magnesium [Chemical symbol] Mg, pronounced "美"
Element No. 13: Aluminum [chemical symbol] Al, pronounced "LV"
Element No. 14: Silicon [chemical symbol] Si, pronounced " Return"
Element No. 15: Phosphorus [chemical symbol] P, pronounced "o"
Element No. 16: Sulfur [chemical symbol] S, pronounced "flow"
p>
Element No. 17: Chlorine [chemical symbol] Cl, pronounced "green"
Element No. 18: Argon [chemical symbol] Ar, A, pronounced "sub"
Element No. 19: Potassium [chemical symbol] K, pronounced "A"
Element No. 20: Calcium [chemical symbol] Ca, pronounced "Beggar"
No. Element No. 21: Scandium [chemical symbol] Sc, pronounced "Kang"
Element No. 22: Titanium [chemical symbol] Ti, pronounced "Tai"
Element No. 23: Vanadium [chemical symbol] V, pronounced "every"
Element No. 24: Chromium [chemical symbol] Cr, pronounced "each"
Element No. 25: Manganese [chemical symbol ]Mn, pronounced "Meng"
Element No. 26: Iron [chemical symbol] Fe, pronounced "Iron"
Element No. 27: Cobalt [chemical symbol] Co, pronounced "Ancient"
Element No. 28: Nickel [chemical symbol] Ni, pronounced "謬"
Element No. 29: Copper [chemical symbol] Cu, pronounced "同"< /p>
Element No. 30: Zinc [chemical symbol] Zn, pronounced "Xin"
Element No. 31: Gallium [chemical symbol] Ga, pronounced "家"
< p>Element No. 32: Germanium [chemical symbol]Ge, pronounced "Zhe"Element No. 33: Arsenic [chemical symbol] As, pronounced "Shen"
No. 34 Element No. 35: Selenium [chemical symbol] Se, pronounced "西"
Element No. 35: Bromine [chemical symbol] Br, pronounced "西"
Element No. 36: Krypton [Chemical symbol] Kr, pronounced "gram"
Element No. 37: Rubidium [Chemical symbol] Rb, pronounced "Ru"
Element No. 38: Strontium [Chemical symbol] Sr, pronounced "思"
Element No. 39: Yttrium [chemical symbol] Y, pronounced "B"
Element No. 40: Zirconium [chemical symbol] Zr, pronounced " "Notice"
Element No. 41: Niobium [chemical symbol] Nb, pronounced "Ni"
Element No. 42: Molybdenum [chemical symbol] Mo, pronounced "M"
p>
Element No. 43: Tc [chemical symbol] Tc, pronounced "got"
Element No. 44: Ruthenium [chemical symbol] Ru, pronounced "了"
Element No. 45: Rhodium [chemical symbol] Rh, pronounced "老"
Element No. 46: Palladium [chemical symbol] Pd, pronounced "Bar"
No. 47 Element: Silver [chemical symbol] Ag, pronounced "silver"
Element No. 48: Cadmium [chemical symbol] Cd, pronounced "spar"
Element No. 49: Indium [ Chemical symbol]In, pronounced "because"
Element No. 50: Tin [chemical symbol] Sn, pronounced "西"
Element No. 51: Antimony [chemical symbol] Sb , pronounced "ladder"
Element No. 52: Tellurium [chemical symbol] Te, pronounced "Emperor"
Element No. 53: Iodine [chemical symbol] I, pronounced "Dian" ”
Element No. 54: Xenon [chemical symbol] ><
p>Element No. 56: Barium [chemical symbol] Ba, pronounced "Bei"
Element No. 57: Lanthanum [chemical symbol] La, pronounced "Blue"
No. 58 Element No. 59: Cerium [chemical symbol] Ce, pronounced "city"
Element No. 59: Praseodymium [chemical symbol] Pr, pronounced "Pr"
Element No. 60: Neodymium [Chemical symbol] Nd, pronounced "female"
Element No. 61: Promethium [Chemical symbol] Pm, pronounced "Po"
Element No. 62: Samarium [Chemical symbol] Sm, pronounced as "shirt"
Element No. 63: Europium [chemical symbol] Eu, pronounced as "有"
Element No. 64: Gadolinium [chemical symbol] Gd, pronounced as " "Roll"
Element No. 65: Terbium [chemical symbol] Tb, pronounced "Intuit"
Element No. 66: Dysprosium [chemical symbol] Dy, pronounced "drop"
p>
Element No. 67: Holmium [chemical symbol] Ho, pronounced "fire"
Element No. 68: Erbium [chemical symbol] Er, pronounced "ear"
Element No. 69: Thulium [chemical symbol] Tm, pronounced "氪"
Element No. 70: Ytterbium [chemical symbol] Yb, pronounced "meaning"
Element No. 71 : Lutetium [chemical symbol] Lu, pronounced "鲁"
Element No. 72: Hafnium [chemical symbol] Hf, pronounced "Ha"
Element No. 73: Tantalum [Chemistry Symbol] Ta, pronounced "tan"
Element No. 74: Tungsten [chemical symbol] W, pronounced "U"
Element No. 75: Rhenium [chemical symbol] Re, Pronounced as "来"
Element No. 77: Iridium [chemical symbol] Ir, pronounced as "衣"
Element No. 78: Platinum [chemical symbol] Pt, pronounced as "波"
Element No. 79: Gold [chemical symbol] Au, pronounced "Jin"
Element No. 80: Mercury [chemical symbol] Hg, pronounced "Arch"
Element No. 81: Thallium [chemical symbol] Tl, pronounced "he"
Element No. 82: Lead [chemical symbol] Pb, pronounced "thousand"
No. Element No. 83: Bismuth [chemical symbol] Bi, pronounced "必"
Element No. 84: Polonium [chemical symbol] Po, pronounced "Pour"
Element No. 85: Astatine [chemical symbol] At, pronounced "Ai"
Element No. 86: Radon [chemical symbol] Rn, pronounced "Winter"
Element No. 87: Francium [chemical symbol ]Fr, pronounced "square"
Element No. 88: Radium [chemical symbol] Ra, pronounced "雷"
Element No. 89: Actinium [chemical symbol] Ac, pronounced "A"
Element No. 90: Thorium [chemical symbol] Th, pronounced "earth"
Element No. 91: Protactinium [chemical symbol] Pa, pronounced "Pu"< /p>
Element No. 92: Uranium [chemical symbol] U, pronounced "from"
Element No. 93: Neptunium [chemical symbol] Np, pronounced "take"
< p>Element No. 94: Plutonium [chemical symbol] Pu, pronounced "No"Element No. 95: Americium [chemical symbol] Am, pronounced "Mei"
No. 96 Element No. 97: berkelium [chemical symbol] Cm, pronounced "bureau"
Element No. 97: berkelium [chemical symbol] Bk, pronounced "accompany"
Element No. 98: californium [Chemical symbol] Cf, pronounced "open"
Element No. 99: Einsteinium [Chemical symbol] Es, pronounced "Ai"
Element No. 100: Fermium [Chemical symbol] Fm, pronounced "Fei"
Element No. 101: Mendeum [chemical symbol] Md, pronounced "Gate"
Element No. 102: Noium [
Chemical symbol] No, pronounced "诺"
Element No. 103: Chromium [Chemical symbol] Lw, pronounced "Labor"
Element No. 104: 鐪[Chemical symbol] Rf , pronounced as "Lu"
Element No. 105: 钅钅[chemical symbol]Db, pronounced as "Du"
Element No. 106: 钅西[chemical symbol]Sg, read "Hi"
Element No. 107: 钅波[chemical symbol]Bh, pronounced "wave"
Element No. 108: 钅黑[chemical symbol]Hs, pronounced "黑" "
Element No. 109: Mt [chemical symbol] Mt, pronounced "马"
Element No. 110: Ds [chemical symbol] Ds, pronounced "Da"
p>
Element No. 111: uub [chemical symbol] Rg, , pronounced "Lun"
Element No. 112: uub (112)
Element No. 113 : uut（113）
Element No. 114: uuq（114）
Element No. 115: uup（115）
Element No. 116: uuh (116)