Official Starting Equations (OSE) for College Physics II
Appropriate identifying labels can be added as subscripts, including replacement of 0 and i by labels associated
with initial states. Component versions of vector Official Starting Equations are also OSE
Vectors are indicated either by arrows above the letter or by the use of boldface.
Frequently-Used Official Starting Equations From College Physics I:
ΣF = ma
Ef – Ei = (Wother)i→f
E=K+U
KE = mv2/2
P = mv
Pi = Pf if ΣFext = 0
General Equations and Mathematics
G
G
F = ∑F
net
i
i
natural log: ln(ex) = x
Electric Charge and Electric Field
G
Q 1 Q 2 , attractive for unlike
F =k
12
r122
G
E
net
=
G
∑ Ei
DC Circuits
Series:
Parallel:
Vab = ε ± IR
V=IR
R=ρL/A
Q
=k
Q
r2
, away from +
G
E = ∆Vi →f /d, away from +
Vnet = ΣVi
C = Kε0A/d
P = q ∆Vi→f / ∆t
1/Ceq = ∑(1/Ci)
Req = ∑Ri
1/Req = ∑(1/Ri) Ceq = ∑Ci
RC Circuit:
charging: V = ε (1 – e-t/RC)
Magnetism
Field due to current and due to charge:
Field outside a long straight wire:
Field of a solenoid:
Parallel wires:
G
E
i
Electric Potential, Electric Energy, Capacitance
Va = (PE)a /q
∆PEi→f = q ∆Vi→f
Wi→f = q ∆Vi→f
VQ = kQ/r = Q/4πε0r
Vdipole= kpcosθ/r2, p = Ql, r>>l Q=CV
Ucapacitor = QV/2 = CV2/2 = Q2/2C
Electric Currents
I = ∆Q/∆t
P = IV = I2R = V2/R
E=F/q
V = V0 e-t/RC
F = I l B sin θ
F = q v B sin θ
B = µ0I / 2πr
B = µ0 (N/l) I
(F / l) = (µ0 / 2π) (I1 I2 / L)
Electromagnetic Induction and Faraday’s Law
φB = B⊥A
ε = N (∆φB/∆t)
ε = B⊥lv⊥
ε = N B A ω sin(ωt)
Electromagnetic Induction and Faraday’s Law (continued
IS / IP = NP / NS
Transformers:
VS / VP = NS / NP
IS / (e IP) = NP / NS
Transformers, efficiency = e: e PP = PS
AC circuits (chapter 18)
Pavg = I02 R / 2 = V02 / 2R
V = V0 sin(2πft)
Irms = I0 / √2
Geometric Optics
plane mirror:
θI = θR
Snell’s law:
n1 sin(θ1) = n2 sin(θ2)
the lens equation
1/dO + 1/dI = 1/f
focal length of spherical mirror: f = r/2
magnification
m = hI/hO = -dI/dO
sign conventions for mirrors:
sign conventions for lenses:
I = I0 sin(2πft)
Vrms = V0 / √2
index of refraction:
n = c/v
total internal reflection: sin(θC) = n2/n1
the mirror equation:
1/dO + 1/dI = 1/f
dO, dI, or f on reflecting side is +
hI is – if image is inverted
f is + for converging lenses and – for diverging lenses
dO is + if object is on side of lens that light comes from
dI is + if image is on opposite side of lens to light source
hI is – if image is inverted