Energy

Mrs. Wolfe

Two Forms of Energy

• Kinetic Energy –

Energy of MOTION

• Potential Energy –

STORED Energy

ENERGY

Time for a game!

• SIMON SAYS!– Kinetic energy: JUMP

– Potential energy: STAND STILL

Kinetic Energy

• Energy of Motion

• KE = ½ mv2

80 km/h truck

50 km/h motorcycle

• Which has the most KE?

• Which has the least KE?80 km/h

50 km/h

80 km/h

Practice Problem:• Homer Simpson sends a bowling ball toward Bart’s

head at a velocity of 200 m/s. The bowling ball has a mass of 20 kg. How much kinetic energy does this ball have?

• KE = ½ mv2

• KE = ½ x 20 x (200)2

• KE = 400,000 J

• *ALWAYS do the square first!!

UNITS!??!• Energy is measured in JOULES (J).

Potential Energy

• Stored Energy

• PE = mgh• G = 9.8 m/s/s

• Which boulder has MORE PE?

Potential Energy

• What other ways can an object store energy?

Look at Potential Energy!

Time for VIDEOS!!

Practice Problem:

• What is the potential energy of EACH plane?• PE = mgh• PE = (800)(9.8)(10,000)• PE = 78,400,000 J• PE = (800)(9.8)(9,000)• PE = 70,560,000 J

Time for a WS then a Lab!

• Kinetic & Potential Energy Math WS

• Kinetic & Potential Energy Lab

Specific Forms of Energy

• Mechanical –

• Thermal –

• Sound –

• Electromagnetic

• Chemical –

Mechanical Energy

• Energy of moving objects– Car traveling down the

road

– Ball flying through the air

– Windup toy walking

– You picking up a glass

Thermal Energy

• Heat Energy; occurs when atoms vibrate faster (friction)– Heating water

– Fire

Sound Energy

• Vibration of atoms in the air that hit our eardrum and register in our brains as sound.– Crackling

– Popping

– Banging

– Etc.

Electromagnetic Energy

• Energy from forces between positive and negative charges in matter.– Electricity

– Magnetism

– Light (includes invisible light such as ultraviolet, infrared, etc.)

Chemical Energy

• Energy that comes from forming or breaking bonds– Signs of a chemical reaction

– Batteries

– Airbags

Transformations of Energy

DEMONSTRATION•Potassium Permanganate + Glycerine = Surprise FIRE!

•List the energy transformations.

Time for a Lab!

• Transformations of Energy Lab

The Law of Conservation of Energy

• Energy cannot be created or destroyed, but it can be transformed.

• Sound familiar? What does this remind you of….?

Pendulum Demonstration

Newton’s Cradle Demonstration

Time for a Lab!

• Basketball Blaster Lab