Energy Stores and Conservation
Ever wondered why rubbing your hands together makes them warm? That's work done against friction transferring energy to thermal stores. Work happens whenever a force moves an object, and it's always equal to the energy transferred.
When you drop your phone, its gravitational potential energy decreases whilst its kinetic energy increases as it speeds up. You can calculate the change in gravitational potential energy using: ΔEp = mg × Δh (mass × gravitational field strength × height change).
Here's the key principle: energy cannot be created or destroyed - it just moves between different stores. In a closed system, no energy escapes to the surroundings, but in real life, some energy always transfers to heat or sound.
Quick Tip: When objects hit the ground without bouncing, their kinetic energy transfers to the surroundings as heat and sound - that's why dropped objects get slightly warmer!
