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Questions. What makes a light bulb light? What do some people have a lot of after eating or drinking something sugary? What do these two things have in common?. Energy. Is the ability to do work. Example: The tennis player does work on her racket by exerting force on it.
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Questions • What makes a light bulb light? • What do some people have a lot of after eating or drinking something sugary? • What do these two things have in common?
Energy • Is the ability to do work. • Example: • The tennis player does work on her racket by exerting force on it. • The racket does work on the ball. • The ball does work on the net
Kinetic Energy • Is the energy of motion. • Kinetic energy depends on mass and speed. • The faster something is moving, the more kinetic energy it has. • Also, the more mass a moving object has, the greater its kinetic energy. WHAT IS MASS? answeronlater slide WHAT IS WEIGHT? answeronlater slide
Potential Energy • Is the energy an object has because of its position. • Example: • The bow has energy because work has been done to change its shape.
Elastic Potential Energy • Energy can be stored in bowstrings, springs, and rubber bands. • You change the shape of these objects by stretching them.
Gravitational Potential Energy • When you lift an object, you do work on it. • You use a force that is against the force of gravity. • Books on a shelf have gravitational potential energy.
Chemical Potential Energy • Before you eat that sugary drink or food, it has the potential to give you energy. • Food and drinks have chemical potential energy due to their chemical composition.
Potential or Kinetic? An apple on a tree.
Potential or Kinetic? A rolling ball.
Potential or Kinetic? A stretched rubber band.
Gravitational, Elastic, or Chemical? Our food and drink.
Gravitational, Elastic, or Chemical? A book on a shelf.
Gravitational, Elastic, or Chemical? A stretched rubber band.
Which one has more Kinetic energy? If Mr. Friel rolled a bowling ball and a soccer ball down the aisle at the same speed, which one would have more kinetic energy? Why?
Which one has more Kinetic Energy? A tennis ball rolling slow or a tennis ball rolling fast?
Mass • Mass – A measure of how much matter is in an object • Mass is not the same as size - some big things, like balloons, are very light, while some small things, like a gold brick, are very heavy. A truck would be the same size whether it was empty or full, but it would have a lot more mass if it was full - and it would be even harder to stop. • Mass is commonly measured by how much something weighs. But weight can change depending on where you are (such as on the moon) while the mass stays the same.
Weight • Weight – The downward force caused by gravity on an object. • Weightcan change depending on where you are (such as on the moon) while the mass stays the same. • Here are some conditions where the Weight might change: in space (can be weightless!) on the moon (a 100 kg mass would weigh 16.6 kg) • An object's mass doesn't change (unless you remove some), but its weight can change.
? • The force of attraction by which terrestrial bodies tend to fall toward the center of the earth.