#AP Physics 2: Thermal Physics - Your Night-Before Guide 🚀

Hey there, future physicist! Let's get you prepped for the AP Physics 2 exam with a focused review of thermal physics. We'll break down the key concepts, highlight must-know formulas, and make sure you're feeling confident and ready to ace this section. Let's dive in!

#1. Thermal Energy Transfer and Equilibrium

#1.1 Thermal Contact and Energy Transfer Between Systems

• Thermal Contact: When two systems can exchange energy through thermal processes. Think of it like a handshake between two objects, where energy can flow 🤝.

• Heating: Energy entering a system via thermal processes.

• Cooling: Energy leaving a system via thermal processes.

• Thermal Processes: The ways energy moves: conduction, convection, and radiation. These are your three amigos of heat transfer!

• Direction of Energy Transfer: Energy always flows from a hotter system to a cooler system. It's like water flowing downhill 🏞️.

• Atomic Collisions: Higher-energy atoms transfer energy to lower-energy atoms during collisions. It's a microscopic game of tag!

• Thermal Equilibrium: When both systems reach the same temperature, and there's no more net energy transfer. It's like a perfect balance ⚖️.

#1.2 Thermal Conductivity

• Thermal Conductivity (k): A material's ability to conduct heat. High 'k' means heat moves easily; low 'k' means it doesn't.

• Fourier's Law: This is the VIP formula for heat transfer:

  $$\frac{dQ}{dt} = -kA\frac{dT}{dx}$$

  • $\frac{dQ}{dt}$ is the rate of heat transfer (how fast heat moves).
  • $k$ is the thermal conductivity (material property).
  • $A$ is the cross-sectional area (size of the heat-transferring surface).
  • $\frac{dT}{dx}$...