Presentation on theme: "Energy Unit E, Chapter 3, Section 1, pE76-77. Energy – Energy: ability to cause changes in matter Objects, with energy can apply forces (push or pull)"— Presentation transcript:
Energy Unit E, Chapter 3, Section 1, pE76-77
Energy – Energy: ability to cause changes in matter Objects, with energy can apply forces (push or pull) – Present around us in many forms Electrical Sound Light Mechanical, etc. – Changes from form to form Electrical energy changes to light energy Mechanical energy changes to thermal energy
Potential and Kinetic Energy Kinetic energy: energy of motion – Can exert a force on matter in contact with it Faster moving object = greater kinetic energy Greater kinetic energy = greater force exerted – So …faster moving objects exert __?__ forces on objects Potential energy: energy due to position (or condition) of an object – Takes energy to lift an object Force of gravity pulling down – Energy is “stored” in the object
Potential and Kinetic Energy Law of conservation of energy: the total amount of energy is a system is always the same – energy cannot be created or destroyed – Object lifted up: Greater the elevation (height) = greater potential energy – More potential energy object has – More energy can be changed to kinetic energy – As an object drops: Potential energy is changed to kinetic energy – Height decreases so potential energy decreases – Force of gravity causes the object’s speed to increase so kinetic energy increases
Potential and Kinetic Energy – As an object rises in the air: Height increases so potential energy increases Gravity causes the object’s speed to decrease so kinetic energy decreases Kinetic energy is changed to potential energy – Law of conservation of energy » Ball stops rising » No kinetic energy » Greatest potential energy
Kinetic Energy – Kinetic energy depends on the mass of objects Bowling ball vs. tennis ball – Both traveling at 20 km/hr (12 mi/hr) – Which one will cause more changes to matter? Why?
Potential Energy – Potential energy depends on the mass of objects Energy cannot be created or destroyed Moving objects with more mass = more kinetic energy Objects with more mass (same height) = more potential energy – Energy cannot be created or destroyed
Potential and Kinetic Energy Pendulum Investigation – What do these two diagrams show?