Questions

Questions(1)What makes a light bulb light?

(2)What do some people have a lot of after eating or drinking something sugary?

(3) What do these two things have in common?

EnergyIs 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 EnergyIs 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? answer on later slide

WHAT IS WEIGHT? answer on later slide

Think of and Share an Example of Kinetic Energy

Potential EnergyIs the energy an object has

because of its position.Example:

The bow has energy because work has been done to change its shape.

Think of and Share an Example of

Potential Energy

Elastic Potential Energy

Energy can be stored in bowstrings, springs, and rubber bands.

You change the shape of these objects by stretching them.

What is gravity?

answer on later slide

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. Weight can 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.