Work & Energy
Slideshow
Edit
1
2
3
4
5
6
7
8
9
10
Work
1. Scientific work meaning
2. Work for constant force
Loading equations
3. Unit of work
The SI unit of work is the joule (J), equal to a newton metre (N m). One joule is the work done when a force of 1 N produces a displacement of 1 m in the force’s direction. Using the same unit for work and energy emphasizes that doing work is a way to transfer energy.
4. Positive and negative work
The sign of work depends on the relative directions of force and displacement. Work is positive when force and displacement point the same way, and negative when the force opposes the displacement (a retarding effect). In lifting, the applied upward force does positive work on the load while gravity does negative work.
Energy basics
5. Energy as capability
Loading equations
Foundations
6. Energy, work, and what “having energy” means
Energy is the ability to do work—meaning to cause a change such as lifting, pushing, heating, or deforming an object. When one object does work on another, energy is transferred from the “doer” to the “receiver.” Energy and work use the same unit, the joule (J), because they measure the same kind of transfer.
Kinetic Energy
7. Kinetic energy: energy of motion
Kinetic energy is the energy an object has because it is moving. A rolling ball, a moving bicycle, or wind can do work by pushing things or causing damage on impact. Motion matters a lot: a small increase in speed can make collisions much more severe because the moving object can transfer much more energy.
8. Key kinetic energy formula (why speed matters so much)
Loading equations
Potential Energy
9. Potential energy: stored energy from position or shape
Potential energy is stored energy that can be released later, often turning into motion. A book on a shelf can fall and do work; a stretched rubber band or compressed spring can snap back and launch an object. In these cases, energy is “held” by position or shape even when nothing is moving yet.
10. Gravitational potential energy and energy conversion
Loading equations







