Energy The ability of a system to do work. Two types of energy: Kinetic Energy Potential Energy
States of Energy All forms of energy can be in either of two states:
What’s the difference? Kinetic Energy is the energy of MOTION Potential Energy is STORED energy.
Kinetic Energy – what does it depend on? The an object moves, the it has. The greater the of a moving object, the it has. Kinetic energy depends on both faster more kinetic energy mass more kinetic energy mass and velocity.
Calculating Kinetic Energy What has a greater affect of kinetic energy, mass or velocity? Why?
Some types of Potential Energy include… Gravitational potential energy Elastic potential energy - Stored energy due to - stored energy due to an objects position (height) - depends on mass of the object and its distance from earth. - Stored energy due to compression or expansion of an elastic object
Calculating Potential Energy OR you could multiply weight (in Newton’s) by height
1. You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. The ball has ___________ energy. Calculate it.
2. A baby carriage is sitting at the top of a hill that is 21 m high. The carriage with the baby weighs 12 N. The carriage has ____________ energy. Calculate it.
3. A car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. The car has ___________energy. Calculate it.
4. A cinder block is sitting on a platform 20 m high. It weighs 79 N. The block has _____________ energy. Calculate it.
5. A roller coaster is at the top of a 72 m hill and weighs 966 N. The coaster (at this moment) has ____________ energy. Calculate it.
6. Two objects were lifted by a machine. One object had a mass of 2 kilograms, and was lifted at a speed of 2 m/sec. The other had a mass of 4 kilograms and was lifted at a rate of 3 m/sec. a. Which object had more kinetic energy while it was being lifted? b. Which object had more potential energy when it was lifted to a distance of 10 meters? Show your calculation.
As a basketball player throws the ball into the air, various energy conversions take place.
Law of Conservation of Energy Energy can be neither created nor destroyed by ordinary means. Energy can be from one form to another. The total amount of is the before and after any transformation or transfer. energy same transformed or transferred
Energy Transfer Energy TRANSFER is the passing of energy from one object to another object. Example: A cup of hot tea has thermal energy. Some of this thermal energy is transferred to the particles in cold milk, in which you put to make the coffee cooler.
Energy Transformation A change from one form of energy to another. Single Transformations Occur when form of needs to be into another to get work done. Multiple Transformations Occur when a of energy transformations are needed to do one energytransformed series work
Energy Transformation An objects energy can be: As velocity kinetic energy and potential energy 1. All Kinetic Energy 2. All Potential Energy 3. A combination of both increases decreases WHAT IS THE TYPE OF RELATIONSHIP KE AND PE HAVE? INVERSE
Roller Coasters Does energy get transferred or transformed? http://www.youtube.com/watch?v=8abzpX CjyjA As you move up to the first hill on a roller coaster the distance between the coaster and the Earth increases, resulting in an increase of Gravitational Potential Energy. At the top of the first hill you have the most Gravitational Potential Energy As you begin your trip down the hill you increase your speed resulting in a transformation from GPE to KE. At the bottom of the hill right before it goes back upward the GPE is small, but the KE is Large. As it starts to move up the next hill or loop KE is transformed back into GPE