Energy Concepts Energy is a fundamental concept in physics, describing the ability to do work or cause change. This topic covers several forms of energy: Kineti...
Energy is a fundamental concept in physics, describing the ability to do work or cause change. This topic covers several forms of energy:
The principle of conservation of energy states that total energy is constant in an isolated system.
Work is done when a force displaces an object, calculated as W = F ∙ d (cosine of angle between force and displacement). The Work-Energy Theorem relates net work done to the change in kinetic energy: Wnet = ΔKE.
Problem: A 2 kg object is lifted 5 m vertically. Calculate the work done against gravity.
Solution: Work = Force * Displacement = mg * h = (2)(9.8)(5) = 98 J
Power is the rate of energy transfer or work done: P = W/t. Units are Watts (J/s). Power relates to forces and velocities as P = F ∙ v.
Many processes involve energy transfers which are not 100% efficient. Efficiency compares useful energy output to total input: Efficiency = (Useful Output) / (Total Input)