CSET Science Physics cheat sheet

Define the system boundary before applying energy conservation.

Constant-force work is F s cos(theta); variable-force work is a signed area or integral.

Net work equals kinetic-energy change for a constant-mass nonrelativistic particle.

m g delta-h is a local uniform-gravity potential-energy approximation.

Mechanical-energy loss can become internal energy while total energy is conserved.

Average power is transferred energy divided by time; instantaneous mechanical power is force dot velocity.

Mitosis preserves starting ploidy; canonical diploid meiosis produces haploid, genetically variable cells

Crossing over (prophase I) and independent assortment (metaphase I) create variation

Replication is semiconservative; the genetic code is degenerate and nearly universal

Glycolysis is cytosolic and nets 2 ATP; aerobic total is about 30–32 ATP

Chemiosmosis via ATP synthase on the inner mitochondrial membrane

Calvin cycle fixes CO2 using RuBisCO in the stroma

Resolve vectors before applying F = ma or the SUVAT equations

Momentum is a vector: conserve each component only when the corresponding net external impulse is zero

Equilibrium requires both zero resultant force and zero resultant moment

The centripetal component points to the centre; uniform circular motion has constant speed but changing velocity

SHM signature: a = −ω²x, giving T = 2π/ω

State g and sign conventions explicitly at the start of a solution

Phase difference = 2π × path difference/λ

Stationary waves: node spacing λ/2, node–antinode λ/4, no energy transfer

Grating equation d sinθ = nλ with d = 1/N in metres

Young's slits: x = λD/a for small angles

Snell: n₁ sinθ₁ = n₂ sinθ₂; critical angle sinθc = n₂/n₁ requires n₁ > n₂

Keep one lens sign convention throughout and state it

hf = φ + KEmax; intensity affects rate, not maximum energy

Threshold frequency f₀ = φ/h in the ordinary single-photon model; below it that model predicts no photoemission

hf = E₂ − E₁ explains line spectra

λ = h/p generally; p = mv for a nonrelativistic massive particle

α: A−4, Z−2; β⁻: Z+1; γ: no change in A or Z

N = N₀e^(−λt) with t½ = ln2/λ; 1 u c² is approximately 931.5 MeV

S-waves cannot pass liquids, revealing a liquid outer core

Divergent, convergent, and transform boundaries produce distinct features

Cross-cutting relationships and superposition establish relative ages

Igneous (intrusive vs extrusive), sedimentary, and metamorphic rocks cycle

Atmosphere: 78% N2, 21% O2; weather occurs in the troposphere

End-Cretaceous extinction linked to asteroid impact and iridium layer

Main sequence stars fuse hydrogen into helium

H–R diagram plots luminosity against temperature; OBAFGKM from hot to cool

Low-mass stars → white dwarfs; massive stars → neutron stars or black holes

Hubble's law v = H0d supports an expanding universe about 13.8 Gyr old

Kepler's third law: P² ∝ a³

Seasons come from 23.5° axial tilt, not orbital distance

Atomic radius falls across a period, rises down a group

Ionic = electron transfer; covalent = sharing; metallic = delocalized electrons

VSEPR: 4 domains = tetrahedral; lone pairs compress angles

Compare the actual substances: hydrogen bonding, dipoles, polarizability and molecular size all affect intermolecular attractions

Limiting reagent is found by converting to moles and dividing by coefficients

pH is logarithmic: each unit is a tenfold change in [H+]

State resolution and uncertainty convention for each instrument

Random errors → repeats and means; systematic errors → correction

For first-order worst-case bounds, add relative contributions; independent standard uncertainties use quadrature

Gradient from two points on the best-fit line, with units

Average repeated timings and time many oscillations to cut reaction error

Never quote more significant figures than the data justify