Potential and Kinetic Energy What is Energy The

Potential and Kinetic Energy

What is Energy? ? ? The ability of an object To do work

Two Main Types of Energy All Energy Potential Energy Gravitation Potential Energy Elastic Potential Energy Kinetic Energy Chemical Potential Energy

What is Potential Energy? o Energy that is stored and waiting to be used later

What is Gravitational Potential Energy? o Potential energy due to an object’s position Don’t look down, Rover! Good boy! o P. E. = mass x height x gravity

ARRGGGG!! NO TRIANGLE Gravity PE Mass Height

Find the Potential energy of a 20 kg bag of dog food elevated 5 meters above the ground on a shelf. Mass = 20 kg PE = mx g x h Height = 5 m PE = 20 kg x 9. 8 m/s 2 x 5 m PE = 980 J

Find the potential energy of a 65 kg climber on top of Mt. Everest ( 8800 m high). Mass = 65 kg PE = mx g x h Height = 8800 m PE = 65 kg x 9. 8 m/s 2 x 8800 m PE = 5 600 J

What is Elastic Potential Energy? o Potential energy due compression or expansion of an elastic object. Notice the ball compressing and expanding

What is Chemical Potential Energy? o Potential energy stored within the chemical bonds of an object

What is Kinetic Energy? o Energy an object has due to its motion o K. E. =. 5(mass x speed 2)

Kinetic Energy Depends on … Mass and Speed

KE = ½ mass x velocity 2 KE = ½ M X V 2 What is the kinetic energy of a 44 kg cheetah running at 31 m/s? Mass = 44 kg KE = ½ M x V 2 Speed = 31 m/s KE =. 5 x 44 kg x (31 m/s)2 KE = 21 142 J

KE = ½ mass x velocity 2 KE = ½ M X V 2 What is the kinetic energy of a 400 kg elevator descending at a rate of 5 m/s? Mass = 400 kg KE = ½ M x V 2 Speed = 5 m/s KE = 400 kg x (5 m/s)2 KE = 5 000 J