10 Kinetic EnergyThe energy of motion is called kinetic energy.
11 Kinetic Energy Kinetic energy depends on both mass and velocity. The faster an object moves, the more kinetic energy it has.The greater the mass of a moving object, the more kinetic energy it has.
12 Let’s Look…..The vehicles below are traveling at the same velocity of 100 km/h. Do they have the same amount of kinetic energy? Why? Why not?
13 AnswerNo, the kinetic energy is different for each vehicle. The truck has a GREATER mass than the motorcycle, so the truck has GREATER kinetic energy.
14 Formula for Kinetic Energy K.E. = mass x velocity22K.E. = m X v2What has a greater affect of kinetic energy, mass or velocity? Why?The velocity does because its value is squared!
15 Let’s Practice..Calculate the kinetic energy of a 3 kg rock that rolls down the hill with a velocity of 2 m/s.K.E. = m X v22
16 Did you get……Calculate the kinetic energy of a 3 kg rock that rolls down the hill with a velocity of 2 m/s.K.E. = 3 X 222K.E. = 6 Joules
17 Quiz Time!Show me what you have learned so far by answering the 4 questions that follow….
18 Question 1Which has more kinetic energy, a large dog sitting on a sidewalk or a small cat running down the street?The large dogThe small catBoth have the same kinetic energyNeed more information to answer
19 Question 2To what property of an object is kinetic energy directly related?VolumeHeightPositionMass
20 Question 3Observe the figure below. Which motorcycle has more kinetic energy? Assuming that the motorcycles have the same mass.Motorcycle AMotorcycle BNeed more informationBA
21 Question 4Elastic potential energy is measured in ________.Kilograms (kg)Newtons (N)Joules (J)Meters per second (m/s)
23 Potential Energy Potential energy is stored energy due to position. Motionless objects havepotential energy!
24 3 Types of Potential Energy Elastic Potential EnergyChemical Potential EnergyGravitational Potential Energy
25 Elastic potential energy- energy stored by something that can stretch or compress
26 Chemical potential energy- energy stored in chemical bonds
27 Gravitational Potential Energy: energy stored by objects ABOVE Earth’s surface Apple
28 Gravitational Potential Energy “The bigger they are the harder they fall” is not just a saying.It’s true!Objects with MORE mass have greater Gravitational potential energy (G.P.E.)
29 Gravitational Potential Energy G.P.E. depends on 3 things:1. Mass of the object2. Acceleration due to gravity = 9.8 m/s23. Height of the object
30 Formula for G.P.E. G.P.E. = mass X 9.8 m/s2 X height G.P.E = m X 9.8 m/s2 X h
31 Let’s Practice..What is the GPE of a 65 kg pole vaulter that is 15 m in the air?G.P.E = m X 9.8 m/s2 X h
32 Did you get……What is the GPE of a 65 kg pole vaulter that is 15 m in the air?G.P.E = 65 X 9.8 X 15G.P.E. = 9555 J
33 Quiz Time!Show me what you have learned so far by answering the 4 questions that follow….
34 Question 1The gravitational potential energy of an object depends on which of the following?Velocity and heightVelocity and weightWeight and heightWeight and acceleration
35 Question 2 A B Which vase has more gravitational potential energy? Vase AVase BCan not determineVase A and B have the same GPEAB
36 Question 3Green plants store energy from the Sun in what form?Light energyElastic potentialGravitational potential energyChemical potential
37 Question 4 Point A Point B Point C Observe the figure on the right. At which point would the roller coaster have the MOST potential energy?Point APoint BPoint CABC
38 Conservation of Energy Energy is most noticeable when it changes from one form to another!Think about it…..
39 Well, probably not until it fell, right? Would you….Would you think that a book on top of a bookshelf as having much to do with energy?Well, probably not until it fell, right?
40 Energy Tranforms…..Energy transforms from one form of energy to another form of energy.Let’s consider……The electrical energy from a light bulb is transformed into what types of energy?Electrical EnergyLight EnergyThermal (Heat) Energy
41 Energy Transforms……….. Potential Energy Kinetic Energy Ball slows downBall speeds up
42 Kinetic vs. Potential Energy At the point of maximum potential energy, the car has minimum kinetic energy.
44 Kinetic-Potential Energy Conversion Roller coasters work because of the energy that is built into the system. Initially, the cars are pulled mechanically up the tallest hill, giving them a great deal of potential energy. From that point, the conversion between potential and kinetic energy powers the cars throughout the entire ride.
45 The Law of Conservation of Energy Energy can not be created or destroyed it can only be converted from one form of energy to another.The total amount of energy in the universe remains constant!
46 Friction converts some mechanical energy to thermal (heat) energy. Rub your hands together. Feel it!
47 Mechanical EnergyMechanical Energy – is the total amount of P.E. and K.E. in a systemM.E. = Total P.E. + Total K.E.
48 Nuclear Fission = nuclei split apart (fission=division) Mass is converted to energy in the processes of fission and fusion.Nuclear Fission =nuclei split apart(fission=division)Nuclear Fusion =nuclei combine(fusion FUSE)
49 The food calorie (C) is a unit used by nutritionists to measure how much energy you get from various foods.1 calorie = joulesKilocalorie = Calorie
50 Quiz Time!Show me what you have learned so far by answering the 4 questions that follow….
51 Question 1What energy transformations occur when a lump of clay is dropped?GPE KE thermal energyKE chem PE thermal energyKE GPE thermal energyGPE KE elastic PE
52 Question 2Suppose a juggler is juggling oranges. At an orange’s highest point, what form of energy does it have?Mostly potential energyMostly kinetic energyNo potential or kinetic energyEqual amounts of both
53 Question 3Which idea is central to the law of conservation of energy?Friction produces thermal energyPeople must conserve energyThe total amount of energy is constantEnergy is the ability to cause change
54 Question 4Friction frequently causes some of an object’s mechanical energy to be changed to which of the following forms?Thermal energyNuclear energyGravitational potential energyChemical potential energy