Presentation on theme: "Produced by Tsang Siu Chung"— Presentation transcript:
1Produced by Tsang Siu Chung WORK DONE & ENERGYProduced byTsang Siu Chung
2Work 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.
3Work = forcedistance moved in the direction of the forceW = F s
4W = F s W = F s cos Joule ( J ) F F F F s s Work is measured by newton metre (N m)Joule ( J )
5Important definition1 joule of work is done when a force of 1 newton moves a distance of 1 metre in the direction of the force.
6Energy ,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!
7Now,we will talking about the mechanical energy. The followings are different forms of mechanical energy.Kinetic energyGravitational potential energyStrain energy
8Kinetic 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.
9Gravitational 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
10Strain 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.
11Work 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.
12Energy in one formEnergy in another formWork is done
13THE 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