Conservative and Non-conservative forces
Links and useful resources
- START HERE: Physics 2024 class outline
- Physics classroom online interactive tools
- OpenSTAX high school physics
- NotebookLM physics notebook
- Physics projects
- AP Physics 1 Dan Fullerton videos
Lightning Round Questions
- (lang) need to practice recognizing prepositions.
- Design a voltage divider that will give you 3.5v from a 5v source.
- When is this expression undefined:
? - If you drop a brick from the first story window, it hits the ground with a certain speed. How much higher would you have to drop from in order to double the speed at the moment of impact?
- What are the basic steps of scientific inquiry?
gr7: [lightning:: 1]
gr10: [lightning:: 3]
- gravity, spring force are conservative
- friction, air resistance, others are non-conservative
Lesson content with examples
What are conservative vs non-conservative forces? A conservative force is one that does the same amount of work no matter what path was taken. It only depends on the displacement of the object in question. Example: Gravity. Your potential energy only depends on your height, it doesn't matter whether you take a wild ride to the bottom of fall in a straight line, if gravity is the only force, then you'll have the same kinetic energy at the end no matter how you get there. This is how roller coasters work, except that they have to deal with....
Friction, which is a non-conservative force. The amount of work done by friction depends on how long the path was - the longer the path, the more time friction has to act on you, and the more work it does to slow you down. If it wasn't for friction, a roller coaster could keep going forever. However, friction is everywhere. That's why a coaster has to have the lifter tracks on the uphill sections to get you back up to the full height of the ride - without those, it would be stuck going over rapidly-shrinking hills because it's energy is being drained any time it's moving.
Systems
Any time you have a system with conservative forces, the energy stays in the system and merely changes form. However, when you have any non-conservative forces in play, energy can enter or leave the system. Most of the time, it's leaving in the form of unrecoverable heat and noise vibrations caused by friction.
When you're making LOL diagrams to represent energy movement at different intervals, the non-conservative forces are the only ones that breach the system boundary.
Media resources
- Youtube search for "gravity, spring force are conservative"
- Youtube search for "friction, air resistance, others are non-conservative"