Andromeda
Note

Potential Energy

Definition

Potential Energy (PE) is energy that is stored and held in readiness. It is energy of position rather than energy of motion.

Why It Matters

Potential energy is the universe’s “debt.” If you lift a weight or stretch a spring, the universe will collect that energy eventually. If you don’t account for this, you’ll be blindsided by a “stationary” object becoming a high-speed projectile (like a failing dam or a snapped cable). It is the essential math for energy grids, safety engineering, and anyone trying to “bank” work for later use.

Core Concepts

  • Gravitational Potential Energy: The energy an object possesses due to its elevated position.
    • PE=weight×height\text{PE} = \text{weight} \times \text{height}
    • PE=mgh\text{PE} = mgh
    • How to read: “The potential energy is equal to the weight times the height, which is also expressed as the mass m times the acceleration due to gravity g times the height h.”
    • Meaning: Gravitational PE—energy stored by lifting mass mm through height hh against gravity gg.
  • Work and PE: The amount of gravitational PE possessed by an elevated object is equal to the work done against gravity to lift it.
  • Reference Level: PE is relative to a reference level (e.g., the ground, a table). Only changes in PE are usually significant in physical calculations.
  • Elastic Potential Energy: Energy stored in a stretched or compressed spring, or a drawn bow.
  • Chemical Potential Energy: Energy stored in the bonds of chemical substances (e.g., fuel, food).

Connected Concepts

Connected notes