physics formulae Flashcards
speed
distance/time
unit: m/s
velocity
displacement/time
unit: m/s
2 formulae of acceleration
when given velocity, initial velocity, final velocity
velocity/time
v-u/t
unit: m/s²
T, time
1/f
1st eq of linear motion
velocity equals??
when given initial velocity, acceleration
u + at
2nd eq of linear motion
displacement, s equals??
when given final velocity, time
1/2(u + v)t
3rd eq of linear motion
displacement, s equals??
just guess bitch
ut + 1/2at²
4th eq of linear motion
velocity squared equals??
when given displacement
u² + 2as
gradient of displacement-time graph represents
velocity
area under graph of velocity time graph is
distance travelled
gradient of velocity time graph is
acceleration
formula for momentum
mass x velocity
unit: kg/ms
formula for elastic collision
m1u1 + m2u2 = m1v1 + m2v2
formula for inelastic collision
m1u1 + m2u2 = (m1+m2)v
formula for explosion
0 = m1v1 + m2v2
hence, m1v1 = -m2v2
formula for force, F
mass x acceleration
unit: N or kg/ms²
formula for force
when given final velocity and time
mv-mu/t
net force
total force - frictional force
impulse, I (2 eq)
when given force, mass, final velocity
Ft
mv-mu
unit: Ns or kg/ms
impulsive force, F
mv-mu/t
force is inversely proportional to
time
weight, W
mass x gravitational acceleration (mg)
unit: N
what is the value of g?
9.8 or 10 m/s²
what is G?
universal gravitational constant
Newton’s law of gravity
F = Gm1m2/r²
gravitational force of body on Earth’s surface, F
GMm/R²
M = mass of Earth (5.98 x 10^24)
R = radius of Earth
gravitational force between Earth & Satellite, F
GMm/(R + h)²
gravitational force between Earth & Sun, F
GMm/r²
centripetal force, Fc
mv²/r
determining mass of sun or earth, M
4π²R³/GT²
values vary according to sun or earth
acceleration of satellites
v² / r
force = ma AND also?
mg
relationship between orbital period, T and radius of orbit
T³/r³ = 4π²/GM
kepler’s 3rd law eq
(T1)² / (R1)³ = (T2)² / (R2)³
speed of satellite
hint: centripetal force = gravitational force
v = square root GM/r
escape velocity
hint: kinetic energy = weight
v = square root 2GM/R
another eq for v
square root 2gG
reading a thermometer temperature
l(θ) - l(ice point) x 100 C
heat capacity, Q
Cθ
unit: J/C
specific heat capacity, c
mcθ
unit: J/kg/C
heat capacity, Q also equal to?
Pt
hence, Pt equal to?
mcθ
unit of power, P
watt, W
specific latent heat, l
ml
when heat transfer involved
mcθ=ml
amount of heat needed to heat ice at 0 C to water at
25 C
mL + mcθ
what is mL stand for
heat needed to change ice at 0 C to water at 0 C
what is mcθ stand for
heat needed to change water at 0 C to water at 25 C
boyle’s law
P inversely proportional to V
PV equal to
constant, k
eq for boyle’s law
P1V1 = P2V2
pressure law
P ∝ T
eq for pressure law
P1/T1 = P2/T2
Charles’ law
V ∝ T
eq for Charles’ law
V1/T1 = V2/T2
frequency, f of waves
number of oscillations/time taken
herts, Hz
wavelength, λ
v = fλ
when you want to compare 2 velocity of wave
v1/λ1 = v2/λ2
capital V stands for
volume
when you want to compare 2 frequency of wave
f1λ1 = f2λ2
that one experiment with two speakers, find distance and whatever
λ = ax (over)
D
what does D stand for
distance between screen and double slit
what does x stand for
distance between fringes
what does a stand for
separation of slit
that diagram where they echo at a wall, how do to find distance
velocity sound x time. (over)
2
electromagnetic spectrum
G - X - U - visible light - I - M - R
going up electromagnetic spectrum, the frequency
increases
going down electromagnetic spectrum, the λ
decreases
speed of light, c
fλ
how many formulas for refractive index, n
4
when given angle of incident and refraction, eq to find n is
sin i/sin r
when given speed of light, eq to find n is
c/v
v = speed of light in medium
value of speed of light
3 x 10^8
when given real depth & apparent depth, eq to find n is
real depth/apparent depth
when given critical angle, eq to find n is
1/sin c
power of lenses, P. if question mintak ans in metre
1/f
power of lenses, P. if question mintak ans in cm
100/f
what is unit of P
diopter (D) or m-1
power of convex lens
+ve
power of concave lens
-ve
linear magnification, m
image distance/object distance Or
image height/object height
when they wanna compare linear magnification, and they give distance & height
image distance. = image height
object distance. object height
focal length, the formula start with 1/f
1/u + 1/v
focal point of convex lens
+ve
focal point of concave lens
-ve
for real image, v (object distance) is
+ve
for virtual image, v is
-ve
for concave lens, v is always
-ve
for convex & concave lens u is always
+ve
focal length of compound microscope
compare between fo and fe
fo < fe
magnification of compound microscope
mo x me
focal length of astronomical telescope
compare between fo and fe
fo > fe
magnification of astronomical telescope
fo/fe
L, distance between 2 lenses
fo + fe
FORM 5
bismillah
in a graph of Fy against Fx, find magnitude of Fx
F cos θ
find magnitude of Fy
F sin θ
sine rule
x/sin opposite x = y/sin opposite y
cosine rule
square root x² + y² - 2xy cosθ
extension of spring
final length - initial length
hooke’s law
force applied ∝ extension of spring
k stands for
spring constant
graph of Hooke’s law x against F
directly proportional
formula Hooke’s law
F = kx
according to graph, the limit is
gradient
the stiffness of spring, the spring constant refer to
gradient
area under graph of Hooke’s law
elastic potential energy
elastic potential energy
1/2 Fx
extension of springs arranged in series
x + x = 2x
extension of springs arranged in parallel
x/2
tension of springs arranged in parallel
F/2
formula for P, liquid pressure
hpg
h stand for
depth of liquid
p stand for
density of liquid
S.I unit for P
Pa
1 Pa equal to
1 Nm-2 or 1 kg m-1 s-2
comparing liquid pressure at 2 different points
P1 = P2
hence, h1p1 = h2p2
atm pressure at sea level
100 000 Pa or 100 kPa
actual pressure
hpg + P(atm)
millimetres of mercury
mm Hg
pascal’s principle
F2/A2 = F1/A1
value for multiplying factor
A2/A1
volume of solid in water is same as
volume of water displaced
volume of water displaced
V = Ah
formula for density, p
m/v
force acting on surface of submerged solid
F = PA
buoyant force, F equal to
pVg
floating object
compare its W to Fb
resultant force
W = Fb
resultant force = 0
sinking object
compare its W to Fb
resultant force
W > Fb
resultant force = downwards
object rising up
compare its W to Fb
resultant force
W < Fb
resultant force = upwards
formula for electric field strength, E at any given point in an electric field
F/q (electric force/quantity of electric charge)
s.i unit for E is for the first formula is
N/C
formula for electric field strength, E produced by 2 parallel charged plates
V/d
s.i unit for E is for the second formula is
V/m
s.i unit for charge is
coloumb, C
formula for current, I
Q/t
S.I unit for current is
ampere,(A)
C/s
formula for potential difference, V if given work done
W/Q
formula for potential difference, V if given energy transferred
E/Q
s.i unit for V
volt, V
J/C
value of charge of an electron
1.6 x 10^ -19 C
1 C is equivalent to how many electrons
6.25 x 10^18 electrons
ohms law
V = IR
current flowing through resistor in a series circuit
I = I1 = I2 = I3
potential difference in a series circuit
V = V1 + V2 + V3
effective resistance in a series circuit
R = R1 + R2 + R3
current flowing through resistor in a parallel circuit
I = I1 + I2 + I3
potential difference in a parallel circuit
V = V1 = V2 = V3
effective resistance in a parallel circuit
1/R = 1/R1 + 1/R2 + 1/R3
compare resistivity of Cu, constantan and nichrome
Cu has lowest resistivity
Nichrome has highest resistivity
formula of resistance, R when given length and area of cross-section of wire
pl/A
p= resistivity of material
formula for ε, emf
E/Q
S.I unit for emf
volt, (V)
J/C
formula for internal resistance, Ir
ε - V
find value of ε when given external resistance and internal resistance
ε = I (R + r)
emf of cells arranged in series
re = r + r + r + r
emf of cells arranged in parallel
1/re = 1/r + 1/r + 1/r
value of current in parallel circuit when given ε and external resistance
ε / R + re
formula for electrical energy when given current
VIt
formula for electrical power, P when given electrical energy
E/t
formula for P, when given current
VI
s.i unit for P
watt (W)
J/s
formula derived from ohm’s law and P when given V
V²/R
formula derived from ohm’s law and P when given I
I²R
total electrical energy is measured in
1 kWh
step down transformer, compare Ns and Np
Ns < Np
step up transformer, compare Ns and Np
Ns > Np
relationship between Ns, Np, Vs and Vp
Vs/Vp = Ns/Np
formula for efficiency, fancy n
output power/input power x 100
relationship between output power and input power
VpIp = VsIs
relationship between Vs and P
VsIs = P
formula of electrical potential energy, E of an electron
eV
relate electrical potential energy with kinetic energy
eV = 1/2mv(max)²
amplification factor of transistor can be found in graph of Ic against Ib by
looking at the gradient
concept of potential divider, how find V(out)
R2. over. x V(in)
R1 + R2
what happens to A and Z in an alpha decay
A - 4
Z - 2
what happens to A and Z in beta decay
A remains same
Z + 1
what happens to A and Z in gamma decay
remains same
concept of half life, what happens No
No/2 - No/4 - No/8
formula to find no of half life, n
t/half life
formula for A, final activity
(1/2)^n x Ao
mass defect, m when given mass before & after fission
mass before fission - mass after fision
formula for energy released during nuclear reaction, E
mc²
value of atomic mass unit, amu
1.667 x 10^ -27 kg
how to convert mass defect in amu to kg
amu x 1.667 x 10^ -27 kg
