Equations Flashcards
density, mass, and volume
p = ( )
density= mass/ volume
p=m/V
Speed
average speed= ( )
average speed= distance moved/ time taken
acceleration
a = ( )
average acceleration= change in velocity/ time taken
a= v-u/ t
force, mass, and acceleration
F = ( )
force= mass x acceleration
F= ma
weight
W= ( )
weight= mass x g
W= mg
moment of a force
moment of force about a point = ( )
moment of a force about a point= force x perpendicular distance from point
stretched spring
F = ( )
load= spring constant x extension
F= kx
pressure and force
p = ( )
pressure= force/ area
p= F/A
pressure in a liquid
p = ( )
pressure= density x g x depth
p= pgh
temperature
kelvin temperature = ( )
kelvin temperature= temperature in degrees celsius + 273
compressing gases
for a fixed mass of gas at constant temperature:
pressure₁ x volume₁= pressure₂ x volume₂
p₁V₁= p₂V₂
heating gases
for a fixes mass of has at constant volume:
pressure₁/ Kelvin temperature₁ = pressure₂/ Kelvin tempterature₂
p₁/T₁= p₂/T₂
Work
W= ( )
Work done= force x distance moved in the direction of force
W= Fd
Gravitational Potential energy
PE = ( )
gravitational potential energy=
mass x gravity x height
PE= mgh
Kinetic energy
KE = ( )
kinetic energy= 1/2 x mass x velocity²
KE= 1/2mv²
Energy and temperature change
E = ( )
energy transferred= mass x specific heat capacity x temperature change
E= mc▵T
Energy and state change
E = ( )
energy transferred= mass x specific latent heat
E=mL
Power
power = ( )
power= work done/ time taken= energy transformed/time taken
Efficiency
Efficiency=
useful work done/ total energy input=
useful energy out put/total energy input=
useful energy output/total energy input
waves
v = ( )
speed= frequency x wavelength
v = f λ
frequency and period
f = ( )
frequency= 1/ period
f= 1/T
refraction of light
n = ( )
refractive index= sine of angle of incidence/sine of angle of refraction
n= sine i/ sine r
Total internal reflection
sin c = ( )
sine of critical angle= 1/ reflective index
sin c= 1/n
charge and current
Q = ( )
charge= current x time
Q=It
resistance, PD (voltage), and current
R = ( )
Resistance= PD/ current
R= V/I
Resistors in series/parallel
series= R= R₁ + R₂
parallel= 1/R= (1/R₁) + (1/R₂)
Electrical power
P = ( )
Power= PD x current
P= VI
Electrical energy
E = ( )
energy transformed= power x time
= PD x current x time
E = Vlt
Transformers
output voltage/input voltage = output turns/input turns
V₂ / V₁= n₂ / n₁
for 100% efficient transformer
power input=power output
V₁ I₁ = V₂ I₂
