FORMULAS

 

ELECTRICITY:

            Power (Watts) = Energy (Joules)/Time (sec)

            Power(Watts) = Current(Amps) * Voltage (Volts)

            Voltage (Volts) = Current (Amps)  * Resistance (Ohms)

            Voltage (Volts) = Energy (Joules)/Charge (Coloumbs)

            -1 Coloumb of Charge = 6.2 * 1018 electrons

            Electric Force is proportional to Charges/Dis2

            Electric Field is Force/Charge

            Series Circuits: Rtot = R1 + R2 ..

            Parallel Circuits: V1=V2, 1/Rtot = 1/R1 + 1/R2

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D= ViT + 1/2 AT2                                                       

Vf2= Vi2 + 2AD                       A=∆V  /∆T                                  

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CONSERVATION OF ENERGY:

            ∆Q  + KE + PE + ∆W =     ∆Q  + KE + PE      + ∆W 

 

KE= M V2                             KE= Kinetic Energy in Joules

PE= M*g*h, g= 9.8 m/sec2     PE =Potential Energy in Joules

∆Work (Joules)= Force (N) * ∆Distance (m) = Pressure (Pa) * ∆ Volume (meters cubed)

 

HEAT ∆Q

Two substances in contact: ∆Q=∆Q for thermal equilibrium

-Increasing/decreasing temperature without changing phase:

(C is the specific heat of a substance changing temperature)

∆Q=m*C*∆T

           

-Changing phase:

 ∆Q=m*Hf for melting/freezing,        ∆Q=m*Hv for vaporizing/condensing 

(Hf and Hv are the heat of fusion and the heat of vaporization for a substance changing phase)

 

Thermodynamics Law 1 Conservation of Energy

Heat Added    = Internal Energy(Temp)     + Work done

∆Q                   =         ∆U                               +  ∆Work 

 

Efficiency = (Thot-Tcold)/Thot (law 2)                      

            T=Temperature in Kelvin

 

Entropy or Order to Chaos, 2nd law

 

WATER: ICE:  C=2090 J/Kg K,  Liquid C=4187 J/Kg K,  STEAM   C=2020 J/Kg K

WATER:                        Hf=335, 000 J/kg                   Hv=2,260,000 J/Kg    

 

Person:            C= 3470 J/Kg K, C for liquid or gas person=1674 J/Kg K

boils at 1700 degrees Celsius

Hf=277633 J/Kg, Hv=1872988 J/Kg,

 

Other conversions:     

Density of Water= 1 gram per milliliter=1000 kilograms per cubic meter

1000 grams= 1 kilogram, 1 kilogram=.001 grams

degrees Celsius= degrees Kelvin- 273

1 Kilocalorie= 1 Calorie = 1000 calories = 4187 Joules

1 Kilowatt Hour = 861 Calories