Questions and Answers
What is the main function of eyes in living organisms?
Receive and process visual detail
What is the role of the optic nerve in the visual system?
Transmit electrical signals to the brain
Which organisms possess image-resolving eyes?
Molluscs, chordates, and arthropods
What is the function of the diaphragm in the eye?
Signup and view all the answers
What percentage of animal species possess a complex optical system?
Signup and view all the answers
What is friction?
Signup and view all the answers
What are the types of friction mentioned in the text?
Signup and view all the answers
What are the consequences of friction mentioned in the text?
Signup and view all the answers
Is friction a fundamental force?
Signup and view all the answers
From what does dry friction arise?
Signup and view all the answers
Study Notes
Friction
- Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
- There are several types of friction, including dry, fluid, lubricated, skin, and internal friction.
Consequences of Friction
- Friction can have dramatic consequences, such as starting a fire by rubbing pieces of wood together.
- Kinetic energy is converted to thermal energy whenever motion with friction occurs, for example when a viscous fluid is stirred.
- Friction can lead to wear, which may cause performance degradation or damage to components.
Characteristics of Friction
- Friction is a non-conservative force, meaning that work done against friction is path dependent.
- In the presence of friction, some kinetic energy is always transformed to thermal energy, so mechanical energy is not conserved.
- Friction is not a fundamental force.
Dry Friction
- Dry friction arises from a combination of inter-surface adhesion, surface roughness, surface deformation, and surface contamination.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
