10-15-12 A DayOBJECTIVE: Students will define

and identify kinetic and potential energy.

• WARM-UP: How does the weight of an apple compare between the earth and the moon?

Homework: Potential and Kinetic Energy Chart- Due WED

10-15-12

• WARM-UP Question: How does the weight of an apple compare between the earth and the moon? Identify where the apple will have less weight. Explain your response.

• WARM-UP Answer: The apple will weigh less on the moon because there is less gravity.

Kinetic and Potential Energy

Definition of Energy…

The ability or capacity to do work.

Measured by the capability of doing work:

potential energy or

the conversion of this capability to motion:

kinetic energy.

Potential Energy…

• Energy due to position or stored energy.

Measure by:PE= (weight) (gravity) (Height)

Potential energy is calculated by:The object’s weight, multiplied by the earth’s gravitational pull (9.8 m/sec sq), multiplied by the distance the object can fall.

Examples of Potential Energy:

Stretching a rubber band.. -Stores energy

Water at the top of a waterfall.. -Stores energy

Yo–Yo held in your hand.. -Stores energy because of position

Drawing a Bow… -Stores energy because of position

• When the position of an object is altered it, creates Potential Energy.

• A yo-yo on the table, doesn’t have energy, but when picked up, it alters its position and now it has the ability (or potential) to do work.

• A bow doesn’t have the capacity to do work, unless it’s held at an elevated position.

Potential Energy Converted to Kinetic

Energy…

When stored energy begins to move, the object now transfers from potential energy into kinetic energy.

Standing still Running

Definition of Kinetic Energy…

The energy of motion.

Measured by:KE= ½ (Mass) (Velocity)

2

Kinetic energy is calculated by one half of the object’s mass,

multiplied by the object’s speed- squared.

Examples of Kinetic Energy…

• Shooting a rubber band.

• Water falling over the fall.

• A Yo-Yo in motion.

• Releasing the arrow from the bow.

Summary of What You’ve Learned..

Example using a coin:• Holding a coin in you hand, alters the

coins original position. • The coin has potential energy,

because it has ability to do work.• Dropping the coin in the bank,

changes the stored energy into motion.

• This transfers the coin’s energy from potential to kinetic energy.

Follow Up Activity…• You will collect at least 5

objects.• You will take these objects

and test to see which has Potential and Kinetic energy or both.

• You can use a Microsoft program such as Excel or Word to make a chart or table organizing your data. You can also use a piece of paper to construct your table.

• Be creative with the objects you choose, and make sure you understand your results to present to the class.

Potential Energy

Kinetic Energy

Both

Example Example Example

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