Energy Stores and Systems
Ever wondered how energy actually exists around us? Energy can be stored in many different forms including gravitational potential, kinetic, chemical, thermal, elastic potential, and others like magnetic, electrostatic, and nuclear.
Energy transfers happen in three main ways: mechanically (when a force does work), electrically (work done by moving charges), or by heating/radiation (like light or sound). In a closed system, neither matter nor energy can enter or leave, so the total energy remains constant.
The kinetic energy of a moving object can be calculated using Ek = ½mv², where m is mass and v is velocity. Similarly, gravitational potential energy uses the formula Ep = mgh, where h is height and g is gravitational field strength. For springs, elastic potential energy follows Ee = ½ke², where k is the spring constant.
Remember this! The specific heat capacity of a material tells us how much energy is needed to raise 1kg of that substance by 1°C. We calculate thermal energy change using ΔE = mcΔθ, where m is mass, c is specific heat capacity, and Δθ is the temperature change.
