Energy Stores and Transfers
When we talk about energy, we're looking at how it's stored in systems (objects or groups of objects) and how it moves around. Energy is always on the move!
For example, when a rolling ball hits a wall, its kinetic energy (movement energy) doesn't disappear—it transforms into sound energy. Similarly, when a car slows down, friction converts kinetic energy into thermal energy (heat). This follows the principle that energy cannot be created or destroyed, only transferred or transformed.
Power measures how quickly energy is transferred and is calculated as: power = energy transferred ÷ time. It's measured in watts (W), where 1 watt means 1 joule of energy is transferred every second.
Remember this! Energy might be "wasted" when it's dissipated into less useful forms, but we can reduce this waste. For instance, lubricating moving parts reduces friction and minimizes energy lost as heat.
