Work+and+Energy

= SECTION 4 =  __ E ____ nergy transformations __

 On a roller coaster going up, kinetic energy is used, but when the roller coaster reaches the top of the track the energy transforms and becomes potential energy, because it is going down.

 __ Potential energy can become kinetic energy __

 When the roller coaster is going down the hill, it starts to change form potential energy to kinetic energy, because once the car reaches the lowest point on the track it isn’t able to go any lower and kinetic energy kicks in so the car will continue up the hill   (This is an illustration of when the rollar coasters car has potential energy and kinetic energy)

 __ Kinetic energy can become potential energy __

 Once the car reaches the top of the hill it starts to run out of kinetic energy and starts to turn into potential energy again, since it’s at the top of the hill the potential energy will carry it down. A car can’t climb a hill taller that the previous hill because it wouldn’t have enough kinetic energy built up.   ( The ball gets thrown up in the air using kinetic energy and when it turns to go down it has a lot of potential energy.After that it has kinetic energy when going down.)  __ Mechanical Energy can change to other forms of energy __

 If changed from kinetic energy to potential energy were always complete then roller coasters would never stop and a ball would always bounce the same hight, but some energy is used to make the noise of a ball hitting the ground, or making the ball slightly warmer after hitting the surface of the ground. When these things happen they are called nonmechanical energy. Every time a ball bounces it loses some mechanical. When energy seems to have disappeared it has just changed to a nonmechanical form.

  (The caption on this illustration says it all)  __ The Law of Conservation of Energy __

 In the Law of Conservation of Energy, energy can’t be created or destroyed. Energy can also not appear out of nowhere. So when it looks like energy just popped up, like when the energy in something increases, it’s because energy entered into the system from an outside force. Energy also doesn’t disappear. So when it looks like energy just disappeared, it’s didn’t it just changed form.

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 17px;"> __ Systems may be open or closed __

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> A system with a pot of water on a burner could be getting very small amounts of energy from the lights in the room, or someone touching the pot, but it would be considered a closed system because all those little things can be ignored. But something like earth would be considered an open system because it gets energy from the sun and it radiates it’s own energy out into space

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 17px;"> __ Not all work done by a machine is useful work. __

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> Friction and other factors make it so only some of the work that a machine does is actually doing what it’s meant to do. For example, using a pulley to lift a sail would be using a ton of extra energy in order to work against the friction of the rope, and the weight of the rope itself.

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 17px;"> __ Efficiency __

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> A quantity (usually expressed as a percentage) that measures the ratio of useful work output to the useful work input is efficiency. The efficiency equation is useful work output divided by useful work input.If a machine is 100% efficient then the work input would be the exact amount of the work done, but no machine is 100% efficient because every machine has friction. A machine can never exceed the work input.

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 17px;"> __ Perpetual motion machines are impossible. __

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> Perpetual motion machines are impossible because in order to have never ending motion you’d have to have no air resistance and no friction. Which can not be done. <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> Here are two more images about Potential and Kinetic Energy.

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> - Image 1 <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> - Image 2

<span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> Here are two videos about Kinetic and Potential Energy... <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> @http://www.youtube.com/watch?v=7K4V0NvUxRg&feature=related <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> @http://www.youtube.com/watch?v=vl4g7T5gw1M

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> Here is a video about the Conservation of Energy <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> @http://www.youtube.com/watch?v=BVxEEn3w688&feature=related

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> <range type="comment" id="795587">Here is a game about Potential and Kinetic Energy <span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> []

<span style="color: #0000ff; display: block; font-family: arial,helvetica,sans-serif; font-size: 13px;"> There will be a demonstration in class about Conservation of Energy and Potential Energy

The six types of simple machines are a lever, a pulley, a wheel and axle, a simple inclined plane, a wedge, and a screw. The lever family While using a hammer it makes it easier to pull out a nail because it uses leverage. Levers are divided into three classes All levers have a rigid arm that turns around a point called the fulcrum. Examples of levers:a pair of pliers is mad of two first class levers, a second class lever is a nutcracker and a hinged door, examples of third class levers, the human forearm. || = Simple = **Machines** [] Smachines.htm
 * Name || Topic || Research || Illustration || Video || Activity || Source ||
 * Jordan || 2 || The six simple machines: lever, pulley, wheel and axle, inclined plane, wedge, screw. Key terms simple machines, and compound machines. Simple machine- one of the six basic types of machines, which are the basis for all other forms of machines. Compound machine- a machine made of more than one simple machine. There are three types of levers: first class levers have a fulcrum located between the points of application of the input and output forces; second class levers, the fulcrum is at one end of the arm and the input force is applied to the other end.The wheel of a wheelbarrow is a fulcrum. Third class levers; multiply distance rather than force. As a result, they have mechanical advantage of less than 1. The human body contains many third class levers. Using a simple machine makes work a lot easier because the amount of force you need to exert is lowered. Mechanical advantage of a lever: mechanical advantage= load/effort. Mechanical advantage of a pulley: mechanical advantage= load/number of ropes. Mechanical advantage of a inclined plane: mechanical advantage=length/height. Mechanical advantage of a wedge: mechanical advantage= length/thickness. Mechanical advantage of a wheel: mechanical advantage= wheel radius/axle radius. Mechanical advantage of a screw: mechanical advantage= number of screws/number of threads. Simple Machines

[] /simple-machines/glossary.htm

-[] examplesofmachines.html

[] phsicsintherealworld/p/ simplemachines.htm || [] [] [] || Kinetic Energy- the energy of a moving object due to the object’s motion Mechanical Energy- the amount of work an object can do because of the object’s kinetic and potential energy
 * lllaruen hou <span style="background-color: #000080; color: #ffffff; font-family: 'Comic Sans MS',cursive; font-size: 20px;">lauren <span style="background-color: #000080; color: #ffffff; font-family: 'Comic Sans MS',cursive; font-size: 1px;">elfldjaifdjoajdofijaoidfjoisjiodfjsoijfdiojsiojdfijsjjj || 3 || Potential Energy- the energy that an object has because of the position, shape, or condition of the object
 * lllaruen hou <span style="background-color: #000080; color: #ffffff; font-family: 'Comic Sans MS',cursive; font-size: 20px;">lauren <span style="background-color: #000080; color: #ffffff; font-family: 'Comic Sans MS',cursive; font-size: 1px;">elfldjaifdjoajdofijaoidfjoisjiodfjsoijfdiojsiojdfijsjjj || 3 || Potential Energy- the energy that an object has because of the position, shape, or condition of the object

Energy: ability to do work measured in joules observed when it is transferred work is only done when an object experiences a change in its position or motion work is measured in joules

potential energy is stored energy if there are two different masses at the same height, the heavier one has more Gravitational Potential Energy if two equal masses are at different heights, the higher one has more Gravitational Potential Energy

once object is moving, it has the ability to do work and has kinetic energy kinetic energy depends on speed and mass an object with more mass with have more kinetic energy than a smaller mass an object with a faster speed with have more kinetic energy than a slower speed kinetic energy depends on speed more than mass

atoms and molecules vibrate, and therefore have kinetic energy the hotter they are, the more kinetic energy they have chemical reactions involve potential energy all living things live from energy from the sun, whether directly or indirectly plants get it directly through photosynthesis then animals eat the plants and get their energy humans eat plants and animals, and we get energy from both

the sun also keeps earth warm and bright the sun’s energy comes from nuclear fusion

electricity is another form of energy that powers things such as appliances, lights, and lightning light energy travels from the sun to earth across empty space in the form of electromagnetic waves light can be separated into a spectrum light toward the blue end carries more energy than the red end ||  ||   ||   ||   ||   ||   || [|Roller Coaster] || [|Potential Energy] || [|Energy Game] || Dobson, Ken, John Holman, and Michael Roberts.//Physical Science//. Austin: Holt Rinehart and Winston, 2004. 391-399. Print. Cheng, Johnny T.. "World of Waterfalls: Featured Articles: Why Do We Care About Waterfalls? ." //World of Waterfalls: Info, Photos, Videos, & More About the World's Waterfalls!//. N.p., n.d. Web. 25 May 2011. || and Courtney! || 4 || __ Energy transformations __
 * Ellen! :D

On a roller coaster going up, kinetic energy is used, but when the roller coaster reaches the top of the track the energy transforms and becomes potential energy, because it is going down.

__ Potential energy can become kinetic energy __

When the roller coaster is going down the hill, it starts to change form potential energy to kinetic energy, because once the car reaches the lowest point on the track it isn’t able to go any lower and kinetic energy kicks in so the car will continue up the hill

__ Kinetic energy can become potential energy __

Once the car reaches the top of the hill it starts to run out of kinetic energy and starts to turn into potential energy again, since it’s at the top of the hill the potential energy will carry it down. A car can’t climb a hill taller that the previous hill because it wouldn’t have enough kinetic energy built up.

__ Mechanical Energy can change to other forms of energy __

If changed from kinetic energy to potential energy were always complete then roller coasters would never stop and a ball would always bounce the same hight, but some energy is used to make the noise of a ball hitting the ground, or I don't car making the ball slightly warmer after hitting the surface of the ground. When these things happen they are called nonmechanical energy. Every time a ball bounces it loses some mechanical. When energy seems to have disappeared it has just changed to a nonmechanical form.

__ The Law of Conservation of Energy __

In the Law of Conservation of Energy, energy can’t be created or destroyed. Energy can also not appear out of nowhere. So when it looks like energy just popped up, like when the energy in something increases, it’s because energy entered into the system from an outside force. Energy also doesn’t disappear. So when it looks like energy just disappeared, it’s didn’t it just changed form.

__ Systems may be open or closed __

A system with a pot of water on a burner could be getting very small amounts of energy from the lights in the room, or someone touching the pot, but it would be considered a closed system because all those little things can be ignored. But something like earth would be considered an open system because it gets energy from the sun and it radiates it’s own energy out into space

__ Not all work done by a machine is useful work. __

Friction and other factors make it so only some of the work that a machine does is actually doing what it’s meant to do. For example, using a pulley to lift a sail would be using a ton of extra energy in order to work against the friction of the rope, and the weight of the rope itself.

__ Efficiency __

A quantity (usually expressed as a percentage) that measures the ratio of useful work output to the useful work input is efficiency. The efficiency equation is useful work output divided by useful work input.If a machine is 100% efficient then the work input would be the exact amount of the work done, but no machine is 100% efficient because every machine has friction. A machine can never exceed the work input.

__ Perpetual motion machines are impossible. __

Perpetual motion machines are impossible because in order to have never ending motion you’d have to have no air resistance and no friction. Which can not be done. || Images of Kinetic and Potential Energy

- Image 1 - Image 2 - Image 3 - Image 4

Mechanical Energy

- image 1 || @http://www.youtube.com/watch?v=7K4V0NvUxRg&feature=related

@http://www.youtube.com/watch?v=vl4g7T5gw1M

[] || Potential and Kinetic Energy game

Demonstration in class ||  ||
 * Cody || 1 || Work is done only when force causes a change in the position or the motion of an object in the direction of the applied force. Work is calculated by multiplying the force by the distance over which the force is applied. Because work is calculated as force times distance, its measured in units of newtons times meters. These units are also called joules. Running up a flight of stairs doesn't require more work than walking up slowly does, but it is more exhausting. Power is the rate at which work is done, that is, how much work is done in a given amount of time. Power is measured in SI units called watts. A watt is the amount of power required to do 1 J oule of work in ! s. Machines help us do work by redistributing the work that we put into them. Machines can change the direction of an input fore. || [] ||  ||   ||   ||