Note
Studied by 7 people
HomeWork, Energy, and Power
Page 1: Introduction to Energy
Energy Concept
Energy cannot be created or destroyed, only transformed.
Integral to understanding kinematics and dynamics.
Energy's incorporation into physics occurred over a century after Newton.
Page 2: Energy Overview
Definition of Energy
Difficult to define precisely; exists in various forms (gravitational, kinetic, potential, etc.).
Governed by the Law of Conservation of Energy: energy cannot appear or disappear in a closed system.
Work and Energy Relationship
Work is the method of transferring energy.
Work is defined as the product of force and distance (W = Fd).
Work is a scalar quantity, can be positive, negative, or zero.
Page 3: Work at an Angle
Work Calculation
Formula for work when force is applied at an angle: W = Fd (cos θ).
Positive work increases speed; negative work decreases speed.
Perpendicular forces do zero work.
Page 4: Examples of Work
Example Calculations
Work done on a crate with a force at an angle.
Normal force does zero work; friction does negative work.
Page 5: Work Done by Gravity
Inclined Plane Example
Work done by gravity calculated using the component of gravitational force parallel to the ramp.
Total work is the sum of work done by all forces.
Page 6: Zero Work and Variable Forces
Zero Work Concept
Forces perpendicular to motion do zero work.
Variable Forces
Work done by variable forces is calculated using the area under a force vs. displacement graph.
Page 7: Kinetic Energy
Definition of Kinetic Energy
Energy of an object due to its motion: K = (1/2)mv².
Work done on an object transfers energy to it.
Page 8: Work-Energy Theorem
Theorem Explanation
A system gains or loses kinetic energy through work.
Positive work increases kinetic energy.
Page 9: Potential Energy
Definition of Potential Energy
Energy stored due to an object's position or configuration.
Examples include gravitational potential energy and energy in springs.