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New Table of Contents Pages 300-309 Energy – the ability to cause change Work is accomplished when a force causes an object to move in the direction of the force ▪ Work = force x distance Measured in joules (J) Named after James Prescott Joule ▪ English Scientist who work to improve electric motors. Study heat and it relationship to work. Paved the way for the theory of the conservation of energy Takes many different forms and has many different effects Ex: Your body uses energy provided by the food you eat and converts it to other forms The two types of energy are called kinetic energy and potential energy Kinetic Energy is the energy of motion The amount of KE that an object has depends on two things: mass and speed(KE = ½ m*s*s) Speed has a greater impact = (KE=mv2/2) Ex: a car and a bike are both moving at the same speed the car has more mass so it has more KE Ex: A cheetah has more KE when it is running than it does when it is walking or sitting under a tree Potential Energy is the stored energy that an object has due to its position One type of PE is called gravitational PE depends on the mass and height of object (GPE = m*9.8*h OR GPE = w * h) Ex: A skydiver has more GPE on the plane than she does after she jumps out and gets closer to the ground Ex: A heavy book has more GPE than a lighter book when they are sitting on the same shelf KE is the energy of motion, but PE is stored energy that can be converted into motion Many objects can have both KE and PE Ex: an object can be both moving and above ground ▪ If you are walking (KE), you still may trip and fall (PE) Mechanical energy is the KE plus the PE due to position (ME = KE+PE) Ex: A skate boarder on a half-pipe has both KE and PE. At the very bottom of the half-pipe, his KE is greatest and his PE is lowest. At the top of the half-pipe, his PE is greatest and his KE is lowest. Ex: Roller Coaster sheet The Law of Conservation of Energy states that energy can neither be created nor destroyed It can only be transformed! Ex: When I pick up a book, I am using my KE to increase the book’s GPE Gravitational Electricity Nuclear Motion Mechanical Radiant (light) Chemical Sound Thermal