Equations Flashcards
Current
Current = Charge/Time I = Q/t
Resistance
Resistance = Voltage/Current R = V/
Voltage in terms of charge and energy
Voltage = Energy/Charge V = E/Q
Power in terms of current and voltage
Power = Current x Voltage P = IV
Power in terms of current and resistance
Power = Current^2 x Resistance P = I^2R
Energy transfer
Energy transfer = power x time
E = VIt
Relationship between number of turns on the primary and secondary coil and the voltages of each in transformers
Vp/Vs = np/ns
Relationship between power at 100% efficiency in transformers
VpIp = VsIs
Speed
Speed = Distance/Time
Velocity
Velocity = Change in Displacement/Time
Acceleration
Acceleration = Change in Velocity/Time
Average Speed
Average Speed = Total Distance/Total Time
Velocity^2 (SUVAT)
v^2 = u^2 + 2as
Energy stored in a stretched spring/strain energy in terms of force
E = 1/2Fx
Energy stored in a stretched spring/strain energy in terms of the spring constant
E = 1/2kx^2
Newton’s Second Law
Force = Mass x Acceleration F = ma
Weight
Weight = Mass x Gravitational Constant W = mg
Momentum
Momentum = Mass x Velocity p = mv
Force in terms of momentum
Force = Rate of Change in Momentum
Work
Work = Force x Distance Moved in Direction of Force
Gravitational Potential Energy
Gravitational Potential Energy = Mass x Gravitational Constant x Change in Height
GPE = mgh
Kinetic Energy
Kinetic Energy = 1/2 x Mass x Velocity^2
KE = 1/2mv^2
Power in terms of energy transfer
Power = Energy Transfer/Time
Percentage efficiency of energy
Percentage Energy = (Useful Output/Total Input) x 100
Specific Heat Capacity
Specific Heat Capacity = Thermal Energy/(Mass x Temperature Change)
Relationship between pressure on a gas and volume at a constant temperature
PV = constant
Density
Density = Mass/Volume p = m/v
Pressure with force
Pressure = Force/Area
Hydrostatic Pressure
Hydrostatic Pressure = Height(Depth) of Liquid x Pressure x Gravitational Constant
Frequency of a wave
Frequency = 1/Time Period f = 1/T
Wave speed in terms of distance and time
Wave Speed = Distance/Time
Wave speed in terms of frequency and wavelength
Wave Speed = Frequency x Wavelength
V = f(lambda)
Relationship between angle of incidence and angle of reflection
Angle of Incidence = Angle of Reflection
Moment
Moment = Force x Perpendicular Distance from the Point to the Line of Action of the Force
Velocity (SUVAT)
v = u + at
Distance (SUVAT with t^2)
s = ut + ½(at^2)
Distance (SUVAT with u and v)
s = ½(u + v)t
Power in terms of force and velocity
Power = Force x Velocity
Impulse
Impulse = Force x Change in Time
Efficiency of energy transfer
Efficiency = (Useful Energy Transfer/Total Energy Input) x 100
Pressure with normal force
Pressure = Normal Force/Area
Spring constant
Spring Constant = Force/Extension
Young modulus
Young Modulus = Stress/Strain
Stress
Stress = Force/Cross-Sectional Area
Strain
Strain = Extension/Un-stretched Length
Refractive index in terms of wave speed
Refractive Index = Speed1/Speed2
Refractive index in terms of angle
Refractive Index = sin(theta1)/sin(theta2)
Refractive index in terms of the critical angle
Refractive Index = 1/sin(Critical Angle)
Charge in terms of current and time
Charge = Current x Time
Potential difference in terms of work done and charge
Potential Difference = Work Done/Charge
Voltage in terms of current and resistance
Voltage = Current x Resistance
Power in terms of voltage and resistance
Power = Voltage^2/Resistance
Resistivity
Resistivity = Resistance x (Cross-Sectional Area/Length)
Relationship between voltage in and voltage out and resistance 1 and resistance 2 in a potential divider circuit
Vout/Vin = R1/(R1 + R2)
Relationship between V1 and V2 and R1 and R2 in a potential divider circuit
V1/V2 = R1/R2
