Conservation+of+Energy

__//Definitions//__
the capacity of a physical system to do work... W = f x d jparadis11

The conservation of energy law states that energy cannot be created or destroyed; it may be transformed form one form to another, but the total amount of energy never changes. -rqureshi

Total energy before = total energy after In a perfect elastic collision, the amt of energy lost is 0.-rqureshi Conservation of Energy is the observation that for a system whose mass does not change, energy is not created nor destroyed. Energy may change forms; energy may be exchanged with the system's environment. Any change in the total energy of the system is accounted for by the opposing change in energy of the system's environment. - MDAT

The Law of Conservation of Energy states that energy cannot be created or destroyed, but can change its form.-MDAT The total quantity of matter and energy available in the universe is a fixed amount and never any more or less.-MDAT Kinetic energy symbols Ek, T or K, is the work required to accelerate an object to a given speed. rqureshi Objects take more work to accelerate to a given speed based on their mass and momentum-mliguori

Potential Energy Elastic potential energy is defined as a work needed to compress (or expand) a spring. The force, F, in a spring or any other system which obeys Hooke's law is proportional to the extension or compression, x, F = − kx where k is the force constant of the particular spring (or system). Hooke's law is a good approximation for behaviour of chemical bonds under normal conditions, i.e. when they are not being broken or formed. ango Energy is a scalar physical quantity. It is a property of objects and systems and is conserved by nature. Energy is defined as the ability to do work.- koolkosmo1 Chemical energy-greatest source of energy used by man. –jyi23 Thermal energy portion of a system that increases with its temperature –jyi23 Energy is converted from one form to another, but it was not created nor destroyed. –jyi23 energy is the ability to do work-sejalP kinetic energy is the energy it has because of its motion-sejalP Kinetic energy is energy in motion-amedina23 Kinetic energy is something such as a car going forward or a tiger jumping on a guy-mliguori When i think of kinetic energy i remember it by thinking of a generator the motion of a generator spinning makes me think of kinetic energy at the energy of motion- aforman Potential energy is stored energy-amedina23 Potential energy is the energy that an object has stored that it could use and Kinetic energy is the energy the object uses when actually in motion jparadis11 work is force times distance-amedina23 Kinetic energy is the energy of motion -blim Potential - An object can store energy as the result of its position -blim Definition of conservation of energy says that the total amount of energy in a system stays constant and can't be recreated, but can change forms. ibabicz Energy is the ability to do work. ibabicz Energy is kinetic when there is motion. Energy is potential when there is not motion but there is just about to be motion. -KatlynB Energy can neither be created nor destroyed. / In terms of mechanical energy Kinetic Energy+Potential Energy=0 Dave S. Kinetic Energy-Work required for a mass to accelerate-Jdao Potential Energy-Energy that an object has because of its position/nature-Jdao Potential energy is stored energy within a system. It can be converted or used later. - elagan Any object in motion has kinetic energy. - elagan KE = (1/2) mv^2 - elagan Kinetic Energy exists whenever an object which has mass is in motion with some velocity - beckym09 Potential energy exists whenever an object which has mass has a position within a force field. -beckym9 work = force X distance -mflosdorf

Energy in a system may take on various forms (e.g. kinetic, potential, heat, light). The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. -Bandrews

__//Pictures//__
-KatlynB

ango

ango

_kquigley

_kquigley _kquigley

blim The energy of the car is transfered to the tree, but it is still conserved.-rqureshi

A pendulum shows conservation of energy -bandrewsSir William Grove, important in discovering the conservation of energy -bandrews

//__Examples out in the world, or real applications of Conservation of Energy__//
Before the yo-yo begins its fall it has stored energy due to its position. At the top it has its maximum potential energy. As it starts to fall the potential energy begins to be changed into kinetic energy-blim

A roller-coaster at the top of its crest, before it starts moving down, has its greatest potential energy. It gains kinetic energy as it gains speed going down the hill and at its lowest point it reaches its maximum kinetic energy. Dave s.

A skier at the top of a mountain has a great potential energy. As he speeds down the mountain, he reaches his maximum kinetic energy. If he goes straight down, this energy will be the greatest at the end of the run. PatMcCaughey

An elevator type cart. When it is dropped down, the potential energy that is stored at the top is converted into kinetic energy. In the real world, where there is friction not a 100% of the potential energy will get converted into kinetic energy. ibabicz

all roller coasters have some sort of energy. when the coaster is not moving, it has potential energy it is about to use and during the way down it has kinetic energy because it is moving .-mflosdorf

Energy is conserved when jumping on a trampoline, it is constantly transferred from springs to the jumper-mliguori

__//Problems//__:
Which person is doing more work, a man holding a 500lbs. barbel over his head, a boy taking 100 lbs. up 5 flights of stairs, or or a car pulling 50lbs. at a constant rate over 10m. The boy that is taking the 100lbs. up five flights of stairs, because he has to do the work for a longer period of time.- koolkosmo1

Work = Force*distance, so I think that kaushik is right because the boy has a greater distance to travel than the others. I guess it depends how long each flight of stairs is. PatMcCaughey

I don't think it's the man holding a barbel over his head because he isn't going any distance. The car is going a short distance and is only carrying 50lbs. I think the boy carrying 100lbs up 5 flights of stairs is doing the most work because work = force times distance and he is going the furthest distance and is carrying more mass than the car. -KatlynB

The boy because the car can easily pull 50lbs, and the man holding 500lbs is not moving. The boy has to do more work as w= f x d. The boy is the traveling the furthest and has to use more force.-Jdao

This problem is flawed from the start. We do not know what kind of car it is. If it is a crappy car, puling 50 pounds may be more work than having the boy, who may be Arnold, carrying 100 pounds up 5 flights of stairs that could be 2 stairs each. So I will go with the man putting 500 pounds over his head because it is the only one I cannot do. jfbutler91

__....................................................................................................................................................................................................__ Can something have energy without having momentum? Explain.

Yes, because there are many forms of energy that are not mechanical. This means that some types of energy do not relate to having momentum in any way. For example, thermal energy does not have momentum. PatMcCaughey yeah because not all energy has to do with momentum and something can still have energy without motion- sejaLP

Yes something that has potential energy does not have to have momentum. jfbutler91 Yes, I agree with John that an object that has potential energy does not necessarity have to have momentum. koolkosmo1 yes because it can have a value of potential energy without actually moving to have a momentum. -mflosdorf

Yes, because momentum has to have action, whereas energy simply requires potential.-Mliguori

__....................................................................................................................................................................................................__ Can something have momentum without having energy? Defend your answer.

Yes an object can have momentum without having energy. Ex: Any object attracted by gravity does need energy to move nor does it give off energy, it is moved by natural universal forces and does not need energy. A meteor hitting the earth does not require energy to move because the earth itself moves it. Dave S. Yes, the force of gravity can act on an object, giving it momentum, but the object, in that case does not require energy. -beckym09 The same is with a vacuum. A vacuum can pull particles into its void without the particles needing to use any energy whatsoever. jfbutler91 Any object free falling has a momentum but it takes no require to just fall jparadis11