Energy and Its Forms Notes

Energy and Work
  • Energy is the ability to do work; work is a transfer of energy.

  • Energy is known by the changes it causes.

  • Work is done when a force moves an object through a distance.

  • Both work and energy are measured in joules (J).

Kinetic Energy
  • Kinetic energy is the energy of motion, depending on mass and speed.

  • Formula: KE=(1/2)mv2KE = (1/2) * m * v^2

  • Example: A 70.0-kilogram man walking at 2.0 m/s has KE=140JKE = 140 J.

Potential Energy
  • Potential energy is stored energy due to position or shape.

  • Gravitational potential energy depends on mass, height, and gravity.

  • Elastic Potential Energy: energy of a stretched or compressed object.

Forms of Energy
  • Major forms: mechanical, thermal, chemical, electrical, electromagnetic, and nuclear energy.

  • Forms: kinetic, potential, and energy in fields.

Mechanical Energy

  • Energy associated with motion and position.

  • Sum of potential and kinetic energy.

Thermal Energy

  • Total potential and kinetic energy of microscopic particles.

  • Increases with faster atom movement.

Chemical Energy

  • Energy stored in chemical bonds.

  • Released energy can do work.

Electrical Energy

  • Energy associated with electric charges.

  • Electric charges exert forces.

Electromagnetic Energy

  • Energy that travels through space as waves.

  • Examples: visible light and X-rays.

Nuclear Energy

  • Energy stored in atomic nuclei by nuclear forces.

  • Released through nuclear fission or fusion.

Assessment Questions