Presentation on theme: "Produced by Tsang Siu Chung"— Presentation transcript:
1 Produced by Tsang Siu Chung WORK DONE & ENERGYProduced byTsang Siu Chung
2 Work done work is done whenever a force moves an object. In everyday language,work may mean anything that people do.In science,it is given a more precise meaning:work is done whenever a force moves an object.
3 Work = forcedistance moved in the direction of the forceW = F s
4 W = F s W = F s cos Joule ( J ) F F F F s s Work is measured by newton metre (N m)Joule ( J )
5 Important definition1 joule of work is done when a force of 1 newton moves a distance of 1 metre in the direction of the force.
6 Energy ,like work, is measured in joule(J). Things have energy if they can do work.We can think of energy as a capacity for doing work in the future.Energy ,like work, is measured in joule(J).BOB!
7 Now,we will talking about the mechanical energy. The followings are different forms of mechanical energy.Kinetic energyGravitational potential energyStrain energy
8 Kinetic energy A moving object has kinetic energy. The faster it moves the more energy it possesses.When a human run,chemical energy from the food changed into kinetic energy.
9 Gravitational potential energy When you lift a box up , it gains gravitational potential energy.The higher the box the more gravitational potential energy it possesses.If the box falls down , its gravitational energy is changed into kinetic energy.BOXGaingravitationalenergyBOX
10 Strain energy Another form of potential energy. It is energy possessed by an elastic object when it is stretched , compressed or bent.If the elastic is released , its strain energy is changed into the kinetic energy.
11 Work done = Energy transferred Energy change and workWork is done whenever energy is transferred from one from to another.Work done = Energy transferredExample:If a falling stone loses 10 joules of gravitationpotential energy and gains 10 joules of kineticenergy , the gravitational force acting does 10joules of work in accelerating the stone.
12 Energy in one formEnergy in another formWork is done
13 THE END “Work done & Energy” This is the end of my project . I hope that you will have a general idea about Thank you.THE END