physic IGCSE

Average velocity (ms-1)

displacement (m)/time (s)

Period of a pendulum (s)

total time (s)/ number of swings

Average speed (ms-1)

distance (m)/time (s)

Acceleration (ms-2)

final velocity (ms -1 ) – initial velocity (ms -1 )/time (s)

Weight (N)

mass (kg) × gravitational field strength (ms-2)

Earth’s gravitational field strength

10 ms^-2

Force (N)

mass (kg) × acceleration (ms^-2)

Density (kgm-3)

mass (kg)/volume (m3)

Hooke’s law

Force (N) = constant (Nm-1) × extension (m)

Pressure (Pa)

force (N)/area (m2)

Fluid Pressure (Pa)

density (kgm-3) × gravitational field strength (ms^-2 or Nkg^-1) × height (m)

Work (J)

force (N) × distance moved (m)

Power (W)

work (J)/ time (s)

Kinetic Energy (J)

½ × mass (kg) × velocity^2 (ms-1)

Gravitational potential energy (J)

mass (kg) × gravitational field strength (ms^-2 or Nkg-1) × height (m)

Efficiency (%)

useful(power/energy) output (W) × 100 /

total (power/energy) input (W)

Moment (Nm)

force (N) × perpendicular distance from pivot (m)

Sum of clockwise moments (Nm)

sum of anticlockwise moments (Nm)

Momentum (kgms-1)

mass (kg) × velocity (ms-1)

Force (N)

change in momentum (kgms -1 )/ time (s)

Impulse (kgms-1 or Ns)

change in momentum (kgms-1)

Centripetal Force (N)

mass (kg) × velocity ^2 (ms -1 )/radius (m)

Orbital Period (s)

2 × π × radius (m) / velocity (ms-1)

Boyle’s Law for changes in gas pressure at constant temperature :

pressure1 (Pa) × volume1 (m^3) = pressure2 (Pa)× volume2 (m^3)

Boyle’s Law for changes in gas pressure at constant temperature2 :

pressure (Pa) × volume (m^3) = constant

energy required

mass (kg) × specific heat capacity (Jkg^-1°C^-1) × temperature change (°C)

Current (A)

charge (C)/time (s)

Voltage (V)

energy transferred (J)/charge (C)

Voltage (V)

current (A) × resistance (Ω)

Power (W)

current (A) × voltage (V)

Power (W)

current^2 (A) × resistance (Ω)

Energy transferred (J)

current (A) × voltage (V) × time (s)

Energy transferred (J)

power (W) × time (s)

Resistors in series:

Total Resistance (Ω)=sum of individual resistors (Ω)

Resistors in parallel:

1/ total resistance (Ω)= 1/sum of individual resistors (Ω)

Resistance (Ω)

resistivity (Ωm) × length (m) / area (m2)

Transformers:

voltage in secondary coil (V) = turns on secondary coil

-----------------------------------------------------------voltage in primary coil = (V) turns on primary coil

Wave speed (ms^-1)

frequency (Hz) × wavelength (m)

Frequency (Hz)

1/Period (s)

Refractive index

sine of the angle of incidence, i /

sine of the angle of refraction, r

Refractive index

speed of light in vacuum /speed of light in material

Refractive index

1 /sine of critical angle

Energy (J)

mass defect (kg) × speed of light2 (ms^-1)