Untitled Lesson

Types of Energy!!!

EQ: What are some forms of

energy and how are they

calculated?

Joules (J)

Unit for energy,
Other unit: Calories
1 Calorie = 4184 J

Potential Energy

-stored energy

Gravitational
Potential
Energy

○ Stored energy based on

height from ground

○ “PEg”

Gravitational Potential Energy

PEg = (mass in kg) (9.8m/s2) (heightin meters)

○ Potential energy does not change based on

the path

Match

Match the correct energy with its description

• Kinetic

• Potential

• Thermal

• Chemical

• Nuclear

Energy of motion

Stored energy

Energy of heat

Energy stored in chemical bonds

Energy stored in atomic nuclei

• Energy of motion

• Stored energy

• Energy of heat

• Energy stored in chemical bonds

• Energy stored in atomic nuclei

Practice!

○ A book is placed on a shelf 2 m high. The

book has a mass of 5 kg. Calculate the PE.

Calculate and answer in your device!

Math Response

A book is placed on a shelf 2 m high. The

book has a mass of 5 kg. Calculate the PE.

Type answer here

Correct Answer: 100

Deg^°

Rad

Practice!

○ A book is placed on a shelf 2 m high. The

book has a mass of 5 kg. Calculate the PE.

Answer: 98J

Elastic
Potential
Energy

PEel= (0.5) (k) (Δx2)

○ k - “spring constant”, how elastic

the spring is, unit is N/m

○ Δx - displacement, change

in position, unit is meters

Practice!

○ A spring with a spring constant of 1.5 N/m

is stretched 0.4m from its resting position.
Calculate the PE.

Calculate and answer in your device!

Practice!

○ A spring with a spring constant of 1.5 N/m

is stretched 0.4m from its resting position.
Calculate the PE.

Answer: 0.12J

Kinetic
Energ y
(“KE”,
“K”)

○ Motion energy

KE = (0.5)(mass in

kg)(velocity2 in m/s)

Don’t forget to square the

velocity!

Practice!

○ A ball with a mass of 3 kg is pushed to a

speed of 10 m/s from rest. Calculate the
KE.

Calculate and answer in your device!

Practice!

○ A ball with a mass of 3 kg is pushed to a

speed of 10 m/s from rest. Calculate the
KE.

Answer: 150J

Mechanical
Energy
(ME)

The total energy (KE + PE) in a

system

Though KE and PE can change,

the total mechanical energy
stays constant

(ME = KE + PE)

(ME = KE + PE)

Law of
Conservatio
n Energy

Energy is not created nor
destroyed;In a closed system
the total energy is constant

MEinitial = MEfinal

so,

PEinitial + KEinitial = PEfinal +

KEfinal

total energy before = total
energy after

Question: What is the answer
in the problem below?

The mechanical energy of an object at the top of

a hill is measured to be 100 J. What is the

mechanical energy of the object when it reaches

the bottom of the hill?

Thermal
Energ y (Th)

○ Heat energy

○ In a mechanical system,

thermal energy is
dissipated (lost) from the
object due to friction