ENERGYKINETIC AND POTENTIAL ENERGY

BY: JESSA PAMONAG

Energy is the ability to do work. All energy can be classified as either __________ or____________

◦ measured in Joules (J)◦ 1 Joule = 1 Nm

Everything that happens in the world uses energy! Most of the time we can’t see energy, but it is

everywhere around us!

What is ENERGY?

is NEVER created or destroyed!

can only be STORED or TRANSFERRED.

Energy…

Batteries store energy!

This car uses a lot of energy

We get our energy from FOOD!

Even this sleeping puppy is using stored energy.

Remember:

ALL matter is made up of particles. The particles NEVER stop moving.

How is all energy divided?

All Energy

Potential Energy

Kinetic Energy

The energy stored in an object.

"Potential" simply means the energy has the ability to do something useful later on.

Potential energy exists whenever an object which has mass has a position within a force field.

Potential Energy is…

PE = mgh(Potential Energy = mass x

gravity x height)

THIS IS THE FORMULA TO FIND POTENTIAL ENERGY :

Calculate the work done by a 50 – kg nurse in lifting 25 – kg child, 0.50 m on the table. both the child and her own weight.

*Suppose her center of gravity also rises about 0.50 m.

Sample Problem:

The energy of a moving object.

"Kinetic" means movement! When stored energy is being used up, it is

making things move or happen.

Kinetic Energy Is…

Examples of Kinetic Energy:

KE = ½mv²

(Kinetic Energy = ½ (mass) (velocity)²

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THIS IS THE FORMULA TO FIND KINETIC ENERGY :

How much energy is required to accelerate a 1000 – kg from rest to 30 m/sec, assuming no friction ?

*Since the car is on level ground and frictions neglected, all of the energy used to accelerate the car goes into energy of motion.

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Sample Problem:

In the case of an object in free fall:When the object is at rest at some height h, then all of its energy is potential. As the object falls and accelerates due to the Earth’s gravity, potential is converted to kinetic. Velocity increases, KE increases; height decreases, PE decreases. At the instant before the object hits the ground, it’s h 0 so it’s PE is zero. All of it’s energy is kinetic.

OTHER KINDS OF ENERGY..

How is all energy divided?

KineticEnergy

All Energy

PotentialEnergy

GravitationPotentialEnergy

ElasticPotentialEnergy

ChemicalPotentialEnergy

o Potential energy due to an object’s position

o P.E. = mass x height x gravity

What is Gravitational Potential Energy?

Don’t look down, Rover!

Good boy!

o Potential energy due compression or expansion of an elastic object.

What is Elastic Potential Energy?

Notice the ball compressingand expanding

o Potential energy stored within the chemical bonds of an object

What is Chemical Potential Energy?