physics
equation of kinetic energy
kinetic energy= 1/2 x mass x velocity²
Ke=1/2mv²
units: joules (J)
equation of Gravitational Potential Energy
GPE= mass x gravitational field strength x height
GPE = mgh
equation of power
power= workdone/time taken= energy transferred/time taken
p= W/t = E/t
equation of efficiency
efficiency= useful energy output/total energy input
or
useful power output/total power input
equation of elastic potential energy
elastic potential energy= 0.5x spring constant²
Ee= 0.5x Ke²
equation of change in thermal energy
change in thermal enegy= mass x specific heat capacity x temperature change
ΔE= mcΔθ
eqution of potential difference
voltage = current x resistance
V=IR
equation of charge flow
charge flow= current x time
Q=I t
equation of resistance in a series curcuit
total resistance = resistance of component 1 + resistance of component 2
Rₜ= R1+R2
equation of resistance in a parralell circuit
total resistance = 1/resistance1 + 1/resistance2
Rₜ= 1/R1 + 1/R2
equation of power
power= current x potential difference
P= I V
power= (current)² x resistance
Energy transferred equatiton
energy transferred = power x time
E=Pt
enegy transferred = charge flow x potential difference E= QV
units joules (J)
density equation
density= mass/Volume
ρ=m/V.
units kg/m^3 or g/cm3
wave speed equation
wave speed = frequency x wavelength
v= f λ
equation of weight
weight= mass x gravitational field stregth
W= mg
work done equation
work done = force x distance
W=Fs
work done equation
work done = force x distance
W=Fs
force acting on a spring equation
force = spring costant x extension
F= k e
moment of a force equation
moment of a force = force x distance (perpendicular to the direction of that force)
M=Fd
pressure equation
pressure = force normal to a surface/area of that surface
P=F/A
distance travelled equation
distance = speed x time
s=vt
acceleration equation
acceleration = change in velocity/time taken a= Δv/t
acceleration = final velocity - initial velocity/ time taken
v-u/t
resultant force equation
resultant force = mass x acceleration
F= ma
momentum equation
momentum = mass x velocity
p= mv
density of solids liquids and gasses
solids are the most dense with very little space between atoms
liquids are less dense than solids but more dense than gas
gases are leats dense with lots of space between particles
measuring regular shape density
use equations for that shape eg a cube, sphere , cone or pyramid
then weigh the object to get the weight then use the the formula density = mass/volume
measuring the density of irregular shaped objects
use an eureka can with a measuring cylinder under the spout add water into the eureka can until it pours out. wjen it stops pouring out remove the water from the measuring cylinder. add the object and after the water stops pouring measure the displacement. then record the weight and use the equation density = mass/volume
what are the changes of state
•freezing - liquid turning to a solid
•melting - solid turning to liquid
•boiling - liquid to gas
•evaporating - when particles at the surface of a liquid have enough energy to turn into a gas
•condensing - gas turning to liquid
•sublimation - solid turnig into gas skipping the liquid stage