(ESSENTIAL) Quantities and units for iGCSE physics (double award) Flashcards
In the equation K.E. = ½mv²
what does the ‘v’ stand for, and what units is it measured in?
Here ‘v’ stands for speed, measured in m/s
In the equation F = kx
what does the ‘F’ stand for, and what units is it measured in?
Here ‘F’ stands for a force (extending a spring) measured in Newtons (N)
In the equation a = Δv ÷ Δt
what does the ‘a’ stand for, and what units is it measured in?
Here ‘a’ stands for acceleration, measured in m/s²
In the equation work done = Fd
what does the ‘d’ stand for, and what units is it measured in?
Here ‘d’ stands for ‘distance moved in the direction of the force.’ It is measured in m.
In the equation average speed = total distance travelled ÷ total time taken, what units is average speed measured in?
Average speed is measured in m/s
In the equation ρ = m ÷ V
what does the ‘ρ’ stand for, and what units is it measured in?
Here ‘ρ’ stands for density. It is measured in kg/m³.(or occasionally in g/cm³)
In the equation W = mg
what does the ‘W’ stand for, and what units is it measured in?
Here ‘W’ stands for ‘weight.’ Since weight is a force, it is measured in Newtons (N)
In the equation G.P.E. = mgh
what does ‘G.P.E.’ stand for, and what units is it measured in?
Here ‘G.P.E.’ stands for ‘gravitational potential energy.’ As with all energies, it is measured in Joules. (J)
In the equation P = F ÷ A
what does the ‘P’ stand for, and what units is it measured in?
Here ‘P’ stands for pressure. It is measured in Pascals. (Pa)
In the equation P₁V₁ = P₂V₂
what does the ‘P₁’ stand for, and what units is it measured in?
P₁stands for ‘initial pressure’. It is measured in Pascals. (Pa)
In the equation Moment = Fd
what does the ‘d’ stand for, and what units is it measured in?
Here ‘d’ stands for ‘distance from pivot.’ It is measured in m.
In the equation Q = It
what does the ‘Q’ stand for, and what units is it measured in?
Here ‘Q’ stands for charge. It is measured in Coulombs. (C)
In the equation V = IR
what does the ‘V’ stand for, and what units is it measured in?
Here ‘V’ stands for voltage. (Sometimes called ‘potential difference.’) It is measured in volts. (V)
In the equation ‘power = energy transferred ÷ time’
what is power measured in?
Power is measured in Watts (W)
In the equation ‘efficiency = useful energy output ÷ total energy input’ what units is efficiency measured in?
Efficiency is a ratio, so it doesn’t have any units. It can be written as a decimal (without units) or multiplied by 100% and written as a percentage.
In the equation P = IV
what does the ‘P’ stand for, and what units is it measured in?
Here ‘P’ stands for ‘power.’ Power is measured in Watts. (W)
In the equation v = fλ
what does the ‘v’ stand for, and what units is it measured in?
Here ‘v’ stands for wave speed.’ It is measured in m/s.
In the equation f = 1/T
what does the ‘f’ stand for, and what units is it measured in?
Here ‘f’ stands for ‘frequency.’ It is measured in Herz. (Hz)
In the equation n = sin(i) ÷ sin (r)
what does the ‘n’ stand for, and what units is it measured in?
‘n’ here stands for ‘refractive index’. Refractive index is a ratio, so it doesn’t have any units.
In the equation sin(c) = 1/n
what does the ‘c’ stand for, and what units is it measured in?
Here ‘c’ stands for the ‘critical angle’ of the material. It is measured in degrees. (°)