Physics Chapter: Energy and Work

Energy and Work

• Forms of Energy and Units:

  • Kinetic Energy (energy of motion): measured in Joules (J)
  • Gravitational Potential Energy (energy due to height): measured in Joules (J)
  • Elastic Potential Energy (energy stored in stretched/compressed objects): measured in Joules (J)
  • Chemical Energy (energy stored in chemical bonds): measured in Joules (J)
  • Nuclear Energy (energy stored in the nucleus of an atom): measured in Joules (J)
  • Internal Energy (energy associated with the microscopic motion of particles within an object): measured in Joules (J)

• Modes of Energy Transfer:

  • Conduction (heat transfer through direct contact)
  • Convection (heat transfer through fluid movement)
  • Radiation (heat transfer through electromagnetic waves)
  • Work (transfer of energy through force acting over a distance)

• Work Definition and Units:

  • Work (W) is the transfer of energy by a force.
  • Measured in Joules (J)

Forces

• Types of Forces:

  • These include contact forces (e.g., friction, normal force, tension) and non-contact forces (e.g., gravitational force, electrostatic force)

• Specific Forces:

  • Centrifugal Force: an apparent outward force felt by an object moving in a circular path.
  • Centripetal Force: the actual force directed towards the center of the circular path, needed to keep an object moving in a circle.
  • Frictional Force: a force that opposes motion between two surfaces in contact.

• Extension–Load Graphs:

  • These graphs show the relationship between the applied force (load) and the extension of an object. Using the graph, one can determine the spring constant and elastic limit of an object.