all equations Flashcards
speed
speed (m/s) = distance (m) / time (s)
d
s t
acceleration
acceleration = change in velocity ( final velocity (m/s) - starting velocity (m/s)) / time
v-u
a t
force
force (N) = mass (Kg) x acceleration (m/s^2)
F
m a
weight
weight (N) = mass x gravitational field strength (m/s^2)
w
m g
energy transferred
work done
efficiency
efficiency = (useful energy output / total input) x 100%
density
density (kg/m^3) = mass (kg) / volume (m^3)
p
m V
gradient
change in distance / change in time
gradient of a distance/time = speed
in a speed-time graph, how do you find the distance?
the area under the line is the distance travelled
1/2 x base x height
how do you find the acceleration from a speed-time graph?
the gradient of the line
what is gravity equal to in acceleration?
10m/s^2
momentum
mass x velocity
m
m v
work done
force x distance moved
kinetic energy
1/2 x mass x speed^2
gravitational potential energy
mass x g x height
pressure
force / area
moment
force x perpendicular distance from the pivot
charge
current x time
voltage
current x resistance
electrical power
voltage x current
wave speed
frequency x wavelength
turns and voltage for a transformer
input (primary) voltage/output (secondary) voltage = primary turns/secondary turns
refractive index, angle of incidence and angle of refraction
n = sin i / sin r i = incidence r = refraction
refractive index and critical angle
sin c = 1 / n
