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(Note: This list may not be exhaustive. Examinees should understand these formulae. Not all of them need to be memorized though. Judgement should be used in deciding which to memorize.)
Formulas for the MCAT (12KB, 1 page)
F = ma
F = Gm1m2/r2
a = v2/r
Static friction = FN mS
Dynamic friction = FN mD
MA = load/effort = number of supporting ropes in a frictionless pulley system
VR = distance moved by effort / distance moved by load = number of supporting ropes
Efficiency = work out / work in
Moment = F x perpendicular distance to pivot point
Momentum = mv
Smv before collision = Smv after collision
Impulse = Ft
PE = mgh
KE = ½mv2
Work done = Fd
Power = Fd/t
Dl = kF
Y = stress / strain = (F/A) / (Dl/l)
S = stress / strain = (perpendicular F/A) / (Dx/l)
B = stress / strain = DP / (DV/V)
f µ Ö (k/m)
T = 2p Ö (l/g)
r = m/V
Upward force on a body = weight of fluid displaced by that body
Hydrostatic pressure = rgh
r 1A1v1 = r 2A2v2
P1 + r gh1 + ½r v12 = P2 + r gh2 + ½r v22
Velocity of sound in a fluid, v = Ö (B/r)
v µ Ö (T/mw)
Velocity of sound in a solid = Ö (Y/r)
Velocity of a wave in a taut string = Ö (tension/[mass/length])
dB = 10log10(I/10-12)
Beat frequency = difference between the two frequencies
f' = f(C±Vd / C±Vs)
F = kq1q2/r²
E = F/q
V = Fd/q
V = IR
For resistors in series, RT = R1 + R2 + R3 + ...
For resistors in parallel, 1/RT = 1/R1 + 1/R2 + 1/R3 + ...
Resistivity = RA/l
C = q/V = permitivity x A/d
For capacitors in series, 1/CT = 1/C1 + 1/C2 + 1/C3 + ...
For capacitors in parallel, CT = C1 + C2 + C3 + ...
P = IV
If a.c., P = (Imax/Ö2) (Vmax/Ö2) = Imax Vmax/2
n1sin i = n2sin r
1/f = 1/u + 1/v
Lens power = 1/f
where f is the focal length in m. Lens power is measured in diopters.
Two lenses in contact:
1/F = 1/f1 + 1/f2
E = hf
At = Aoe-kt
t½ = ln2/k
PV = nRT
KE µ T
v µ Ö(T/mw)
PT = P1 + P2 + P3 + ...
P = mole fraction of solvent x Po
DP = mole fraction of solute x Po
DTBP = kb (molality of solute particles)
DTFP = -kf (molality of solute particles)
Osmotic Pressure = RT [molarity of solute particles]
pH = -log10[H+]
pOH = -log10[OH-]
Kw = [H+] [OH-] = 10-14 (at 25oC)
Ka = [H+] [A-] / [HA]
pKa = -log10Ka
Kb = [HA] [OH-] / [A-]
pKb = -log10Kb
Ka Kb = 10-14
pKa + pKb = pKw = 14
pH = pKa + log10[A-]/[HA]
DE = q - w
DG = DH - TDS
DG = DG° + RTlnQ
Keq = eDG°/-RT
Reaction Order | dA/dt | Integrated Forms |
0 | dA/dt = k | At = A0 - kt |
1 | dA/dt = kA | At = A0e-kt |
2 | dA/dt = kA2 | 1/At = (1/A0) + kt |
E = E° - (RT/nF)lnQ
= E° - (0.026/n)lnQ
Keq = enFE°/RT
DG° = -nFE°