notes 15-1 “energy and it’s forms”. * k.e. is the energy associated with motion. i. kinetic...

Notes 15-1 “Energy and It’s Forms”

* K.E. is the energy associated with motion.

I. Kinetic Energy

A. K.E. is a state of energy not a form of energy.

B. Anytime a moving object has the ability to do

work that object has K.E.

C. Usually the faster an object is moving the more

K.E. it has.

a. K.E. is directly related to the velocity.

D. If 2 moving objects have the same velocity, the

object with a greater mass has a greater K.E.

E. K.E. is calculated with the formula

K.E. = Mass x (velocity)2/2

F. Mass and velocity are directly related to the K.E.

a. if either mass or velocity increases then the K.E. also increases.

G. Velocity has the greater affect on the K.E.

H. An object at rest will have no K.E. because the velocity is 0.

Ex) What is the K.E. of a fast ball thrown by a major league pitcher if the baseball has a mass of .70kg and his pitch is clocked at 46.49m/s?

II. Potential Energy

A. The energy of position.

B. P.E. does not have the ability to do work

because it is not moving.

C. Instead with P.E. the object is storing

energy that was given to the object when

work was done on it.

D. An object with P.E. has the ability to give

that energy back through a transfer.

III. Gravitational Potential Energy

A. This is the amount of energy associated

with height.

B. The higher an object is the more G.P.E.

the object has.

C. The weight of an object also determines

the amount of G.P.E.

a. the more an object weighs the more

G.P.E. it will have.

D. The equation to calculate G.P.E. is:

G.P.E. = Weight x Height

Ex) A 1.8 kg cat climbs upwards 12 meters to sit on the roof of a house.  How much potential energy does it possess while it sits enjoying the sunshine?

Ex) A boulder has 5000 J of potential energy while sitting on top of a cliff.  If the cliff is 250 m above the ground, what is the weight of the boulder?

IV. Forms of EnergyA. Mechanical Energy

a. the sum of an objects P.E. and K.E.b. the energy associated with motion. c. does not include thermal energy.d. does not include the motion of things

at the atomic level. B. Thermal Energy

a. the total PE and KE of all the microscopic particles in an

object. b. when an objects atoms move faster,

its thermal energy increases.

C. Chemical Energy

a. the energy stored in chemical bonds.

b. the energy that is released when

your body digests food.

c. the energy released when a car burns

gasoline.

d. any chemical bond will release

energy when the bond is broken.

D. Electrical Energy

a. the energy associated with a moving electrical charge.

c. batteries convert chemical energy

into electrical energy.

d. lightning is another example of

electrical charge.

E. Electromagnetic Energy

a. the form of energy that travels through space in the form of waves.

b. visible light, x-rays, GPS, satellites

are all dependant on electromagnetic

waves.

F. Nuclear Energy

a. the splitting of the nucleus of an

atom.

b. atomic bombs release nuclear

energy.

c. nuclear power plants (Hanford) use

nuclear fission to generate electricity.

d. the heat and light generated from the

sun are