(ESSENTIAL) Equations for IGCSE physics (double award) Flashcards
State the equation for average speed
average speed = total distance travelled ÷ total time taken
State the equation that relates acceleration, change in speed and time taken
a = Δv ÷ Δt
Δv means change in speed, Δt means change in time
State the equation that relates the resultant force on an object to its acceleration
F = ma
State the equation that relates the force applied to a spring to its extension
F = kx
State the equation for kinetic energy
K.E. = ½mv²
Give the equation for work done
Work done = Fd
Give the equation for density
ρ = M ÷ V
can also be written as D = M ÷ V
Give the equation for weight
W = mg
State the equation for gravitational potential energy
G.P.E. = mgh
State the equation for pressure
P = F ÷ A
Give equation that relates the initial pressure and volume of a sample of gas to its final pressure and volume (Boyle’s law)
P₁V₁ = P₂V₂
Give the equation for calculating the turning effect or ‘moment’ of a force
Moment = Fd
Give the equation that relates charge and current
Q = It
Give the equation that relates voltage and resistance
V = IR
State the equation that relates power and energy transferred
power = energy transferred ÷ time
State the equation for efficiency
efficiency = useful energy output ÷ total energy input
you can write efficiencies decimals, or you can muliply by 100 and leave an efficiency as a %
State the equation that relates power, voltage and current
P = IV
State the wave equation, that relates wave speed, wavelength and frequency
v = fλ
Give the equation that relates the frequency of a wave to its time period
f = 1/T
or T = 1/f, which is the same equation, rearranged
State the law of reflection
angle of incidence = angle of reflection
Give the equation that relates the refractive index of a material to the angle of incidence and the angle of refraction
n = sin(i) ÷ sin (r)
What is the equation that relates the refractive index of a material to the critical angle, for that material?
sin(c) = 1/n
What equation can be used to calculate the pressure at a depth ‘h’ below the surface of a liquid?
P = ρgh
notice that density here is shown as the greek symbol ‘ρ’, NOT the letter ‘p’!
What equation relates stopping distance, thinking distance and braking distance?
stopping distance = thinking distance + breaking distance
What equation relates temperature in °C to temperature in K?
Temperature in °C = Temperature in K - 273
Give the equation that relates instantaneous speed to change in distance and change in time
v = Δd ÷ Δt
Δd means change in speed, Δt means change in time
