Energy

Energy Energy Capacity to do work SI unit of energy joule 2 Classes of Energy Kinetic Potential F:\chemistry\chemistry\energy\08_02Ene rgyConcepts_A.html

5 Forms of Energy? 5. Nuclear Energy: the nucleus of an atom is split 1. Chemical: Energy existing within the bonds that hold atoms together Ex: fuel, coal, food 2. Mechanical: Matter that is in any type of motion Ex: water coming down a waterfall, wind, car, airplane, walking, playing tennis 3. Electromagnetic: Moving electric charges which have energy to perform work. Ex: electric motors, light, colors of the rainbow, radio waves 4. Heat: The internal motion of atoms that are constantly in motion. Ex: forms of matter changing from solids to liquids then gas, heat energy is observed by temperature changes. 5. Nuclear Energy: the nucleus of an atom is split Ex: the sun’s energy, nuclear weapons Applying_the_Concepts_of_Energy.asf

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Conservation of Energy Energy is not created it is just converted or changed to a different form Law of conservation of Energy Albert Einstein’s Theory of Relativity If a system or body gives off energy it decreases in mass If there is an absorption of energy there is an increase in mass

What is Gravitational Potential Energy? Boardworks High School Science Gravitational and Potential Energy What is Gravitational Potential Energy? The GPE of an object can be calculated using this equation: GPE = mass x gravitational field strength x height Mass is measured in kilograms (kg). Gravitational field strength is measured in newtons per kilogram (N/kg), usually taken as 10 N/kg on Earth. Teacher notes An alternate version of the equation is ‘GPE = weight x height’, as ‘weight = mass x gravitational field strength’. Gravitational field strength can also be referred to as gravity. Height is measured in meters (m). GPE is measured in joules (j).

Boardworks High School Science Gravitational and Potential Energy Factors affecting GPE Teacher notes This activity could be used to introduce the factors affecting the GPE of objects, and the ‘GPE = mgh’ equation.

Boardworks High School Science Gravitational and Potential Energy Calculating GPE An eagle with a mass of 2 kg flies at a height of 200 m above the ground. How much gravitational potential energy does the eagle have? GPE = mass x gravitational field strength x height Photo credit: © 2007 Jupiterimages Corporation = 2 x 10 x 200 = 4,000 J

Boardworks High School Science Gravitational and Potential Energy Calculating GPE An apple with a mass of 200 g falls 3 m from its branch to the ground. How much GPE will the apple have lost when it reaches the ground? = mass x gravitational field strength x GPE lost change in height Photo credit: © 2007 Jupiterimages Corporation = 0.2 x 10 x 3 = 6 J

Boardworks High School Science Gravitational and Potential Energy Teacher notes This multiple-choice activity provides an opportunity for students to practice using the ‘GPE = mgh’ equation. Students could answer each question in their books before revealing the answer on the interactive whiteboard.