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GPE. and how to calculate it. reminder mass and weight. Mass: how much substance in something , measured in Kgs (kilograms) Weight: the force acting on the mass of an object due to gravity, measured in N (newtons) . Reminder types of energy. types of potential energy. Chemical:
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GPE and how to calculate it
reminder mass and weight Mass: how much substance in something , measured in Kgs (kilograms) Weight: the force acting on the mass of an object due to gravity, measured in N (newtons)
types of potential energy • Chemical: • possessed by foods, fuel and batteries • Elastic: • possessed by stretched springs, elastic and rubber bands • Gravitational: • possessed by anything which can fall
what is gravitational potential energy ? • This is a type of energy possessed by anything that is a height above the ground, such as a roller coaster, a book you raise from the floor or an apple about to fall from a tree
A simple example Height above ground So has potential energy No height above ground No potential energy Height
What happens to the Gpe when something falls ? • Energy is conserved: the GPE that an object loses is converted to kinetic (movement) energy as an object falls. Don’t worry to much about this we’ll cover it in a future lesson
How do we calculate GPE We can CALCULATE gpe BY USING A SIMPLE EQUATION: Potential Energy = weight X height But remember that: weight =mass x g so Potential Energy=mass X g X height
What are the letters in the equation? • P.E: potential energy, measured in joules (just like every other type of energy) • m: mass of the object measured in Kgs • g: Gravitational field strength on earth, a constant 10 N/kg • h: the height between the floor and the object
A worked example • Tony hawk has a mass of 80kgs • He has a height above the ground of 2 meters • What is his GPE?
Worked example part two Using P.E.=m X g X height P.E.=80x10x2 P.E.=1600J 2 m
A question for you • Tony hawk has just jumped a vert ramp. He is 10 meters from the floor. His mass is 80 kg. What is his GPE?
solution Weight =mass x g P.E=weight x height Mass =80kgs g=10N kgs height=10m P.E.= 80Kgs x 10N/kg X 10m P.E.=8000J
Some further questions • A 1kg mass is raised 1m from the floor what is its GPE? • A ball has a mass of 0.5 Kgs. It is 15 meters high. What is its GPE? • A roller coaster has a GPE of 150000J at the top of its loop. Its mass is 1000kgs. What height is the top of the loop. • An paper aeroplane has a mass of 0.01kgs, it reaches a height of 4m. What is its GPE? • Remember that g= 10N/kg