Work Done by Forces
This page introduces the concept of work done by forces in physics. The fundamental formula for calculating work is presented:
W<sub>AB</sub>(F) = AB × F × cos(AB, F)
Where:
- W<sub>AB</sub> is the work done
- AB is the displacement
- F is the force
- cos(AB, F) is the cosine of the angle between the force and displacement vectors
Definition: Work is the product of force, displacement, and the cosine of the angle between them.
The page then explores different scenarios of work:
- Motoring work: When the force is in the same direction as displacement (0°), resulting in positive work.
- Resistive work: When the force opposes the displacement (180°), resulting in negative work.
- Null work: When the force is perpendicular to the displacement (90°), resulting in zero work.
Example: For a weight force P, the work is calculated as W<sub>AB</sub>(P) = m × g × (Z<sub>A</sub> - Z<sub>B</sub>), where Z<sub>A</sub> and Z<sub>B</sub> are the initial and final heights.
The page also introduces the concepts of conservative and non-conservative forces:
Highlight: Conservative forces, like gravity, do not depend on the path taken, while non-conservative forces, like friction, do depend on the path.