IGCSE Triple Physics Formulae

Average speed (m/s)

Speed (m/s) = Distance moved (m) / Time taken (s)

Acceleration (m/s^2)

Acceleration (m/s2) = Change in Velocity (m/s) / Time taken (s)

Weight (N)

Weight (N) = mass (Kg) × gravitational field strength (N)

Force (N)

Force (N) = Mass (Kg) × Acceleration (m/s2 )

Momemtum (kg m/s)

Momentum (Kg m/s) = Mass (Kg) × Velocity (m/s)

Force acting

Force acting = Change in momentum (Kg m/s) / Time taken for change to happen (s)

Moment

Moment (Nm) = Force (N) × Perpendicular distance between line of action and pivot (m)

Orbital speed

Orbital speed (m/s) = 2 × π × orbital radius (m) / Time period (s)

Electrical power (watts)

Electrical power = Current (amps) × Voltage (volts)

Energy transferred (joules)

Energy transferred = Current (amps) × Voltage (volts) × Time (s)

Voltage (V)

Voltage = Current (amps) × Resistance (Ohms)

Charge (coulomb)

Charge = Current (amps) × Time (s)

Wave speed (m/s)

Wave speed (m/s) = Frequency (Hz) × Wavelength (m)

Frequency

Frequency (Hz) = 1/T (period) (s)

Snell's Law

n = sin i / sin r

Critical angle

sin C = 1 / n

Efficiency

Efficiency = Useful energy *output* / Total energy *input*

Work done (joule)

Work done (J) = Force (N) × Distance moved (m)

Power (watts)

Power (W) or (J/s) = Work done (J) / Time taken (s)

Kinetic energy (joules)

Kinetic energy (J) = 1/2 × mass × speed2

Gravitational Potential Energy (GPE) (joules)

GPE = m (Kg) × g (10 m/s2) × h (m)

Density (kg/m^3)

Density (g/cm3 or Kg/m3) = mass (Kg) / volume ( __ 3)

Pressure (pascals)

Pressure (Pa) = force (N) / area (m2)

Pressure difference (pascals)

Pressure difference = height (m) × density (g/cm3 or Kg/m3) × g (10 m/s2)

pressure and volume equation

P1V1=P2V2

pressure and temperature equation

P1/T1 = P2/T2

transformer equation

Vp/Vs = Np/Ns

transformer efficiency equation

Vp x Ip = Vs x Is

Power supplied

Power = Voltage (volts) × Current (amps)

Magnetic Field around a straight wire

Magnetic field around a flat circular coil

Magnetic field of a solenoid

Flemming's Left Hand Rule

Thumb = Force
Second finger = Field
Third Finger = Direction of Current

Flemming's Right Hand Rule

Thumb = Force
Second finger = Direction of Field
Third Finger = Direction of Current

Newton's First Law

Balanced forces mean no change in velocity

Newton's Second Law

A resultant force means acceleration

Newton's Third Law

For every action there is an equal and opposite reaction

total anticlockwise moment =

total clockwise moment

red shift

change in wavelength / reference wavelength = velocity of galaxy / speed of light