Covers topics 1 to 4: Energy, Electricity, Particles, and Atomic Structure (Nuclear Physics)
Relevant for double combined Trilogy and triple or separate physics
Pause if more time needed to understand
Energy
Total energy in any interaction is conserved: Cannot be created or destroyed (except conversion between mass and energy
for triple students in nuclear fision and fusion)
Types of energy stores: Kinetic, Gravitational Potential (GPE), Elastic Potential, Thermal, Chemical Potential (no equation)
Formulas:
Kinetic: $e = \frac{1}{2} mv^2$
Gravitational Potential (GPE): $e = mgh$
Elastic Potential: $e = \frac{1}{2}k e^2$
Thermal energy: $e = m c \Delta T$ (Specific Heat Capacity, SHC)
Energy transfer: Energy moves from one object/store to another, must conserve total energy (closed system)
Example: Roller coaster - GPE turns into KE, use $gpe_{lost} = ke_{gained}$ to find speed
Efficiency: Useful energy output vs total energy input: Efficiency $= \frac{\text{Useful energy out}}{\text{Total energy in}}$
Practical: Specific Heat Capacity (SHC)
Using electric heater in metal cylinders: Measure change in temperature, calculate energy input, use rearranged SHC equation
Issues with heat loss to surroundings
Power
Definition: Rate of energy transfer, $P = \frac{E}{T}$, unit is Watts (W)
Example: Laptop power supply calculation, rearranging the equation to find energy usage