Science Notes 3 PDF

Intro to Energy and Kinetic Energy that it to its motion...

Intro to Energy and Kinetic Energy that it to its motion applied to object causes change Work : force is an When ↳ Effort push/force pull Energy : movement/ability to do work ↑ ↳ Need energy to be able to change ↳ Capacity to be able to change an objects motion In physics that if you have done ENERGY is transferred to another object or changed into something different , we say work , do work which that it Energy is the ability to means can more object over distance - an a - Energy has no mass or volume lie. Energy is not matter) Types of Energy Energy GravitationaPotential ~ I /orical - ↓ Electrical - > Light Kinetic - > Elastic ↳ ↓ sound ↳ Mechanical electrical ↓ Nuclear Thermal Kinetic Energy : object result of its motion Kinetic energy of as Energy (KE) a - is the an transformed they collide into other of - Kinetic energy can be transferred between objects when or types energy ↳ Units :The SI(system international) Unit of Kinetic energy is jouls , abbreviated J Calculating Kinetic Energy The Formula for Kinetic energy is : KE = Emr - m is the mass of the object in kg - v is the speed of the object in mys kinetic energy in J - Ke is the Remember from math there is a correct order of operations /BEDMAS) ↳ brackets, exponents , divison , multiplication addition, , subtraction Potential Energy stored inside of objects because of their position inside of the object, their charge Potential Energy (PE) stresses or - is the energy , - The name means that PE stored inside of an object is not useful until it is released and transformed into another type of energy /motion , heart) ; in other words , it is the "potential to create other types of energy - Example : a stretched bow contains potential energy that is released when the archer releases the bowstring , this becomes Kinetic energy in the arrow - There are several kinds of potential Energy , we will only focus on the PE of objects in Earth's gravity - The S1 unit of potential Energy is Jorks , abbreviated J  Acceleration Doe To Gravity - All objects with mass a re attracted downwards toward Earth by gravity to accelerate towards the Earth in what is known as the acceleration of gravity-19 8 m/s objects. - This causes all - Despite What common sense tells you, the acceleration of gravity does not depend on mass : all objects accelerate towards earth at the same rate airl they would at the same time person and feather from the top of YHS (in complete both land the concrete Example If you drop vaccum a > no - a on Height: surface there is within the object - The height of an object above the farth's determines how much potential energy above Earth's the object has greater the height sur face more of -The , an - The S1 unit of height is meters , abbreviated m Calculating Potential Energy The formula for potentialfnergy is : Pf = mgh is - m is the mass of the object kg - g is the acceleration of gravity in m/s2. It is always 9 8. m/s(on Earth) - h is the height in m - He is the potential energy in J Conversion of Units meters height: cm = 0 am. km = 1 , 000m Mass : Kilograms gram = 0. 001 kg milligram = 0. 000001 kg Types of Energy #attaI Refinition and Example I -o Mechanical The energy of motion of objects that are larger than atoms or molecules ex. any object that is moving has mechanical energy waves that travel orradiate from Radiant The energy of electromagnetic an energy source. Ex. Lightbulbs /radiate or radiation, visable light , and infrared radiation. EX. the sun radiates the entire electromagnetic spectrum (solar energy) - energy known as "heat energy" ; energy from the movement of particles within a substance , related to its tempature. E. boiling water gains thermal energy from the store , causing its molecules to more faster Energy other conductor load electrical of electrons moving along a wire or. Ex. A lany appliance) changes the electrical KE into another form such as radiant energy (light bulb) Most o-  I Energy Type Definition and Example Energy stored stretched or compressed object not just elastic hands or springs ex soles flastic in a , of shoes , tennis ball and racket · - westdinamabods cal much human societiesone main ae energy stored in fossil fouls. ex. fireflies turn chemical potential energy to light gravitation ground ex. roller coaster at the top of a large hill has more 46 than at the bottom Energy stored within of release Nuclear the nucleus an atom. Nuclear processes can an enormous of energy. Ex nuclear power plant radioactive decay -ric amount. , - Me andboaandmademetoaquina e battery magnetic and is attracted Earth's magnetic feild. it's by Magnetic A compass needle moves because Energy can be transferred or Transformed - The total amount of energy present before energy is transfered or transformed , is always exactly equal to the total energy present afterwards - In other words energy , is neither created or destroyed Total Energy After - Total Energy Before = out ↳ Energy in = Energy Law of conservation of thergy The law of conservation of energy states : neither created destroyed it is transformed from on e form of energy to another or transformed from one object to another Energy is nor , Energy Transfer vs transformation of between objects and remains in the same type energy Energy Transfer : when energy moves Energy Transformation : When energy moves between objects and the form of energy changes Recall Billard balls : when one pool ball strikes another , mechanical Kinetic energy is transferred from one ball to another. It is also transforms into sound which "lost" into and thermal energy are the surroundings. Example : Energy Transformation in a Pendulum end which is free to swing At the start top of the Swing the has kinetic energy (it is not A pendulum is a mass on the of a string. , mass no moving) but has potential energy lequal to its mass and height) acceration due to As it falls , the PE of the mass is transformed into kinetic energy as the pendulum gains speed due to the gravity upwards again , the KE of the mass is transformed back into At as the mass slows down and gains height back to the top of the swing As it swings => eating A To a falling parachute a TV Solving solve catapult food set law of conservation law of of energy problems conservation , always start with the formula of energy problems below than use the question to identify which have value and which energies to Then isolate for the needed variable energies a are set zero. Formula: KEinital + PEinital = Keinal + Pral Energy Chains and called energy chains Energy transformations can happen one after another , are Ex chemical potential energy > electrical energy > heat energy + light energy flashlight - A - : -. Energy Efficiency energy transformation energy is wasted heat the surroundings During some as to - an , energy The less wasted energy the efficient the device - , more For a torch chemical energy light energy stored in the (useful energy) battery energy heating up torch + room (wasted energy) effiency of device amount of useful energy produced 100 % a X = total energy transformed Ex. What is the efficiency of a l0W light bulb that uses 1005 of energy and loses TST as heat energy ? Step 1 : how much useful light energy is produced ? ↳ 255 calculate efficiency 2 2 : Step = x100 = 25 %  Potential and Kinetic Energy Examples : - Batteries store energy -cars use lots of energy - We get our energy from food - Even sleeping puppies use stored energy KMT : - All matter is made up of particles - The particles never stop moving - these particles have energy Conservation of Energy Roller Coasters : roller coaster have - When does the train on a the most potential energy ? ↳ At the very top the train is lifted by the motor, the more potential energy is produced - the higher At the very top of the hill the train has a huge amount of potential but very little kinetic energy. - energy , - When does the train on this roller coaster have the most kinetic energy ? ↳ At the bottom of the tallest hill amount of Kinetic energy -There is very little potential energy at the bottom of the hill, but there is a great down the hill the potential is converted into As the train accelerates energy Kinetic energy - The sum of energy (f) is constant all of closed system is accounted for, the total energy (f) will not change over time - If the energy a - Efinital = *Efinal ↳ -Sigma-mathematical n Recall : closed system - "extra energy is not added to or removed from the 'system. Heat Energy - Heat energy is given off when friction is involved of the total at the end - We consider En as being part energy Efinial Ete Ear involved , we'll put for = ↳ term here + > if heat is