Equations Flashcards
Kinetic Energy equation?
kE = 1/2 x m x v^2
Kinetic Energy = 1/2 x Mass x Velocity (Squared)
Joules = 1/2 x kg x metres per second (m/s)
Gravitational Potential Energy equation?
GPE = g x m x h
Gravitational Potential Energy = Gravitational Field Strength x Mass x Height
Joules = Newtons per Kilogram x Kilograms x Metres
Tip to remember - Give Me Hope
Specific Heat Capacity equation?
E = m x c x ∆θ Energy = Mass x SHC x Temperature Change Joules = Kilograms x J/Kg/°C x °C
Elastic Potential Energy equation?
EPE= 1/2 x K x e^2 Energy = 1/2 x Spring Constant x Extension^2 Joules = 1/2 x N/m^3 x metres
Energy when a substance changes state?
Tip - Specific Latent Heat equation
GIVEN IN EXAM - but become familiar with it
E = m x L
Energy for a change in state = Mass x SLH
Efficiency equations?
- Efficiency = Useful Energy Out / Total Energy In
- Efficiency = Useful Power Out / Total Power In
Note - Efficiency MUST be a decimal below one.
Charge equation?
Q = I x t Charge = Current x Time Coulombs = Amps x Seconds
Ohm’s Law (Voltage)?
V = I x R Voltage = Current x Resistance Volts = Amps x Ohms
Energy in a Circuit?
Equation
E = Q x V Energy = Charge x Potential Difference Joules = Coulombs x Volts
Power in a Circuit equation? (1)
Tip - think glue
P = V x I Power = Voltage x Current Watts = Volts x Amps
Tip = Remember PVA (like the glue)
Power equation? (2)
Tip - think pirate
P = I^2 x R Power = Current^2 x Resistance Watts = Amps x Ohms
Power equation? (3)
Tip - think Barney
P = E/t Power = Energy / Time Watts = Joules / Seconds
Tip - THINK PET
Density equation?
p = m x V Density = Mass x Volume Kg/m^3 = Kg x m^3
In a transformer, power must be conserved. Give the equation that supports this.
Vp x Ip = Vs x Is
Voltage x Current (in the primary) = Voltage x Current (in the secondary)
Essentially use the power equation on each side of the iron core.
Mass and weight equation?
W = m x g Weight = Mass x Gravitational Field Strength Newtons = Kg x N/Kg
