Chapter 8 energy In Physics work and energy

Chapter 8 energy In Physics, work and energy are two concepts that are closely linked. When work is done on an object by an external force, the object gains energy and the external force loses energy. Work done on the object equals the amount of energy transferred from the external force to the object.

Chapter 8: Energy

Kinetic Energy

Light Energy

Thermal Energy

Electrical Energy

Potential Energy

Nuclear Energy

Sound Energy

Mechanical Energy

Types of Energy We make use of different types of energy to help us do work in our everyday lives. potenti al nuclea r soun d mechanic al Chapter 8: Energy kinetic Types of Energy light therma lelectric al

Energy The SI unit for energy and work done is Joules, J. Energy is closely associated with work. It is defined as the ability to dohave work. § If you more energy, you can do more work. § In order for work to be done, energy must be converted from one form to another. § Similarly, when energy is converted from one form to another, work is done. Chapter 8: Energy

Defining Work The work done, W, by a force on an object is given by the product of the force, F, and the distance, d, moved by the object in the direction of the force. Work = Force × distance in the direction of applied force N m The SI unit for work done is Joules (J). 1 joule is defined as 1 newton-metre 1 J = 1 Nm Chapter 8: Energy

Work Done (a) Work done against friction Work is done against friction when a force is applied to move an object in contact with a surface over a certain distance. Work done = Force × distance = 3. 0 N × 10. 0 m = 30. 0 J (b) Work done against gravity Work is done against gravity when a force is applied to lift an object to greater height in a gravitational field. Chapter 8: Energy

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