Physics O Levels Formula Sheet
1) Speed
= distance / time
s = d / t (in symbol)
unit = km/h , m/s , cm/s
2) Acceleration
= change in velocity / time
a = v - u / t (v = final speed, u = Initial Speed, t = Time)
unit = m/s2
3) Average Speed
= total distance travelled / total time taken
s = d / t
unit = km/h, m/s, cm/s
4) Velocity
= displacement / time
v = dis / t
unit = m/s, km/h, cm/s
5) Force
= mass x acceleration
F = ma
unit = N (newton)
6) Weight
= mass x gravitational field strength
W = mg
unit = N (newton)
7) Density
= mass / volume
ρ = m / v
unit = g/cm3, kg/m3
8) Moment
= Force x perpendicular distance
m = F x d
unit = Nm (newton meter)
9) Principal Of Moment
sum of clockwise moment = sum of anticlockwise moment
F x d = F x d
10) Extension
= loaded length - unloaded length
x = L - l0
unit = mm , cm
11) Pressure
= Force / Area
p = F / A
unit = Pa (Pascal) , N/m2
12) Liquid Pressure
= density x gravity x height of the liquid
P = p g h
unit = Pa, N/m2
13) Pressure volume relationship of a gas
initial pressure x initial volume = final pressure x final volume
P1 V1 = P2 V2
14) Pressure transmission
initial force / initial area = final force / final area
F1 / A1 = F2 / A2
15) Kinetic Energy
= 1/2 x mass x (velocity)2
KE = 1/2 mv2
Unit = J (Joule)
16) Potential Energy
= mass x gravity x height
PE = mgh
unit = J
17) Work done
= Force x distance (travelled in the direction of force)
W = F x d
unit = J
18) Power
= work done or energy supplied/ time taken
p = W / t
unit = W (Watt) , KW (kilo watt)
19) Efficiency
= energy output / energy input x 100
Or
= power output / power input x 100
Unit = %
20) Heat Capacity
= thermal energy / change in temperature
C = E / Δ T
unit = J/0C
21) Specific heat capacity
= thermal energy / mass x change in temperature
c = E / m ΔT
unit = J/kg °C , J/g °C
22) Specific latent heat
= thermal energy / mass
l = E / m
unit = J/kg , J/g
23) Wave Equation
speed of wave = frequency x wavelength
v = f λ (λ is wavelength)
24) Frequency
= 1 oscillation / time taken
f = 1 / t
unit = Hz
25) Electrical Power
= Voltage x Current
Or
= (voltage)2 / Resistance
Or
= (current)2 x resistance
p = VI , p = V2/R, p = I2/R
unit = W (watt) , KW (kilo watt)
26) Refractive index
n= sin i / sin r (when going from rarer to denser medium)
Or
n= sin r / sin i (when going from denser to rarer medium)
Or
n = 1 / sin c (c is the critical angle)
27) Resistance
= Voltage / Current
R = V / I
unit = Ω (ohm)
28) Current
= charge / time
I = Q / t
unit = A (ampere) , mA
29) Electromotive force
= work done / charge
e.m.f.= E / Q
unit = V
30) Potential difference
= work done / charge
p.d = E / Q
unit = V
31) Resistance is series
R= R1 + R2 + R3 …
unit = Ω
32) Resistance in parallel
1/R = 1/R1 + 1/R2 + 1/R3 . . .
Or
R = R1 x R2 / R1 + R2
unit = Ω
33) Temperature
θ = Xθ - X0 / X100 - X0 x 100 (θ is the unknown temperature and X is the physical property of the thermometric substance)
34) Electrical energy
= voltage x current x time
Or
= power x time
E = VI , E = Pt
unit = J, KWh
35) Cost of electricity
= energy in KWh x cost per unit
36) Hook's Law
= F1 / x1 = F2 / x2 (F is the force and x is the extension)
- You can rearrange any of the equation according to the question. These are important formulas and other formulas can be made by changing the subject of the equation.
