formulae Flashcards
avg speed formula
avg speed = distance moved / time taken
final velocity formula
v² = u² + 2as
v = final velocity
u = initial velocity
s = distance travelled while accelerating
a = acceleration
formula only works when acceleration is constant
acceleration formula
acceleration = change in velocity/ time taken
(v-u)/t
(a negative value means deceleration - slowing down)
formula only works when acceleration is constant
weight formula
weight = mass x gravitational strength
w = mxg
Force (N)
mass (kg) x acceleration (m/s^2)
F=ma
stopping distance
thinking d + braking d
voltage
current x ressistance
V = IR
charge (C)
current x time
Q= It
energy transfered (J)
charge x voltage
E =QV
or
charge x current x ressistance
E = QIR
electrical power (w)
current x voltage
P=IV
energy transfered (electrial appliances)
current x voltage x time
E = IVt
wave speed (m/s)
freq (Hz) x wavelength (m)
v = f x λ
angle of incidence
= angle of reflection
refractive index
speed of light in a vaccum/ speed of light in materical
n = c/v
snells law
refractive index (n) = sin i / sin r
snell and critical angles
sin C = 1/n
efficiency
useful energy output/ total energy output x 100
work done (J)
force (n) x distance moved (m)
W=Fd
power
work done / time taken
energy in kinetic energy store
1/2 x mass x speed²
1/2 x m x v²
energy in gravitational potwntial energy store
mass x gravitational field strength x height
