Transcript Energy - White River High School

7/18/2015
What is energy?
Where does it come from?
How is it made/used up?
Pre-Test
Vocabulary Introduction
1. What is energy, and it’s unit of measure? (2)
2. Identify ALL variables in the following equations
(2)
a) PE=mgh
b) KE=1/2mv2
3. What is the potential energy of a toy car with
mass .1kg on a 2m high shelf?
4. What is the Kinetic Energy of a bullet train with
mass 20,000 kg with a velocity of 50m/s
 Unit: Energy
 Section – Types of
Energy
 Pretest
 Vocab Cover Flip
 Hamburger
 Trim The Fold
 Share your ½ sheet
 Hamburger
 Hotdog
 Trim Both Folds
 Hold Vertical
 Fold top edge 1cm
 Glue into book sideways
Vocab Foldables
 On the front…
 Vocab Word
 On the Inside…
 Your own definition
 1 use or fact
 Illustration about word




Energy
Potential Energy
Kinetic Energy
Conservation of
Energy
7/18/2015
What does it mean to have potential?
What are some areas you have heard
the word potential used?
Types of Energy
 Textbook definition:
 The ability to do work.
 What that really
means:
 The ability to make
something happen
 Honestly…
 No one really knows
what energy is, we can
only describe how it is
manifested!
 Energy is Measured
in Joules (J)
 Mechanical Energy
 Potential Energy
 Elastic
 Gravitational
 Kinetic Energy
 Other
 Thermal Energy
 Chemical Energy
 Nuclear Energy
 Potential Energy
 Stored Energy
 Gravitational PE
 A skydiver
 A boulder teetering on
a cliff
 Elastic PE
 Bow & Arrow
 Slingshot
 Spring
We will mostly use gravitational PE in class
 Two Factors
 Height & Weight
 Weight = mass x gravity (9.8m/s2)
 So…
PE  m gh
 What is the PE of Mr. Simo’s Heisman Trophy?
(Shown Below)
25kg
1.0
m
Find 4 separate items
around the room
 For each Item…
 Sketch the item &
location
 Measure the mass
(kg)
 Measure the height
from the ground (m)
 Calculate the PE (j)
using PE=mgh
Example:
M=2k
g
H=1.5
m
PE  m gh
PE  2  9.8 1.5  29.4 J
 Kinetic Energy
 Energy of Motion
 Two Factors
 Mass & Velocity
 So…
1
2
KE  mv
2
If I go twice as fast,
how much does my
KE increase?
 Mr. Simonson once got a speeding ticket for
going 45 mph (20m/s) in his radical ‘86 transam, (m=1,500kg). My Kinetic energy should
have been 181,500J, what was it?
Ex Credit: what was the speed limit?
Conservation of Energy
Potential Energy
Kinetic Energy
 It has always been
around!
 Even before the big
bang!
 Energy CANNOT be
created
 Energy is never used
up…
 Energy transfers from
one object to another
 Energy CANNOT be
destroyed!
Energy Has NO
kryptonite...
Awesome!
 Conservation of
Energy
 Energy is neither
created nor destroyed,
it merely changes
form!
 PE transfers to KE & Vice Versa
The total amount of mechanical Energy in the diagram below will always
be 50,000 j. The energy levels of KE & PE change according to height &
velocity…
 Find the energy value in the blanks for each
scenario…