WJEC Physics for A2: Student Bk

8 Overview: Unit 3 Oscillations and nuclei 3.1 Circular motion p10 The period of rotation, frequency, speed and angular velocity of rotation. Angles expressed in radians. Centripetal acceleration and force. The use of the following equations relating to circular motion. v = ω r a = ω 2 r a = ν 2 r F = m ν 2 r F = m ω 2 r 3.2 Vibrations The definition and characteristics of simple harmonic motion (shm). a = – ω 2 x and its solutions x = A cos ( ω t + ε ) and ν = – A ω sin ( ω t + ε ) . The graphical representation of shm – the variation of kinetic and potential energy. Shm in spring systems and the simple pendulum. Damped free oscillations including critical damping and the effect of damping in real systems. Forced oscillations and resonance – practical examples. PRACTICAL WORK Measurement of g with a pendulum. Investigation of the damping of a spring. p21 3.3 Kinetic theory p38 The molar gas constant and the Boltzmann constant. The equation of state for an ideal gas, pV = nRT . The assumptions of the kinetic theory of gases; p = 1 3 ρ c 2 = 1 3 N V mc 2 . The Avogadro constant, the mole, molar mass; k = R N A . The mean translational kinetic energy of the molecules of a gas, 3 2 kT . 3.5 Nuclear decay p66 The spontaneous nature of nuclear decay; the nature of α , β and γ radiation, nuclear equations; A Z X . Nature, range and penetrating power of α , β and γ radiation. Background radiation. Activity, A , the decay constant, λ and half-life T 1 2 . The radioactive decay equation, A = λ N and the solutions: N = N 0 e – λ t , A = A 0 e – λ t , N = N 0 2 x , and A = A 0 2 x . The derivation and use of λ = ln 2 T 1 2 . PRACTICAL WORK Investigation of radioactive decay using a dice analogy. Investigation of the variation of intensity of gamma radiation with distance. 3.6 Nuclear energy p83 The meaning and use of E = mc 2 . The unified atomic mass unit ( u ); calculations of nuclear binding energy and binding energy per nucleon. The conservation of mass / energy to particle interactions including fission and fusion. The binding energy per nucleon curve. The relevance of the binding energy per nucleon to nuclear fission and fusion. 3.4 Thermal physics p51 Thermodynamic systems and their boundaries. Internal energy, U and the first law of thermodynamics, Δ U = Q – W . Calculations using W = p Δ V , W = the area under a p – V graph and U = 3 2 nRT . In practical terms Δ U = Q for solids and liquids. Thermal equilibrium as the definition of temperature equality; absolute zero as the minimum energy state. Temperature differences determining heat flow, Q = mc Δ θ . PRACTICAL WORK Estimation of absolute zero by use of the gas laws. Measurement of the specific heat capacity for a solid. WJEC Physics for A2 Level: Unit 3