AQA Physics GCSE - Energy Changes

AQA Physics GCSE 4.1.1 - Energy Changes in a System Vocabulary Flashcards

Kinetic Energy Equation

½ m v² where Energy is in Joules (J), Mass is in kilograms (kg), and Velocity is in meters per second (m/s)

Elastic Potential Energy Equation

½ k x² where Energy is in Joules (J), Spring Constant is in Newtons per meter (N/m), and Extension is in meters (m)

Gravitational Potential Energy Equation

mgh where Energy is in Joules (J), Mass is in kilograms (kg), Gravitational Field Strength is in Newtons per kilogram (N/kg), and Height is in meters (m)

Specific Heat Capacity

The amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius.

Units for Specific Heat Capacity

Joules per degree Celsius per kilogram (J/°C/kg)

Power

The rate at which energy is transferred (or rate at which work is done).

Equations for Power

power = energy transferred/time OR power = work done/time, where Energy and Work Done are in Joules (J) and Time is in seconds (s)

Unit of Power

Watt (W)

Energy changes of a ball thrown upwards (no air resistance)

Upwards: Kinetic energy (KE) is converted to Gravitational Potential Energy (GPE). Peak: Maximum GPE, zero KE. Downwards: GPE is converted to KE.

Energy transfers for a bungee jumper

When falling, GPE is converted to KE. As the cord tightens, KE is converted and stored as Elastic Potential Energy (EPE). At the lowest point, the jumper’s initial GPE equals the EPE stored in the cord.

Chemical Energy Stores Examples

Food, Fuel (e.g., wood, coal, petrol), Batteries

Different stores of energy

Kinetic Energy, Gravitational Potential Energy, Elastic Potential Energy, Chemical Energy