Transcript The point in the middle of a pulley is like the fulcrum of a lever and

Wednesday, March 3rd
Agenda
Quick Review of section 8.2
Finish section 8.2
The Inclined Plane Family
In-Class Assignments:
Section 8.2 review, pg. 262, #1-4
Section 8.2 study guide
Quiz over section 8.2
“The Pyramids” Worksheet
Inclined Plane Quick Activity
Quick Review
What is the definition of a simple machine?
One of the six basic types of
machines of which all other
machines are composed.
Quick Review
List the 6 Simple Machines
1.Simple lever
2.Pulley
3.Wheel and axle
4.Simple inclined plane
5.Wedge
6.Screw
Quick Review
What are the 3 classes of levers and how are
they different from each other?
1. 1st class levers
Fulcrum in middle
Input and output forces at opposite ends of arm
2. 2nd class levers
Fulcrum at one end of arm
Input force applied to opposite end of arm
3. 3rd class levers
Fulcrum at one end of arm
Input force applied in middle of arm
Quick Review
How is a pulley like a lever?
The point in the middle of a pulley
is like the fulcrum of a lever and
the rest of the pulley acts like
the arm.
What is it called when multiple pulleys are put
together into a single unit?
Block and tackle
Quick Review
How are a wheel and axle like a lever?
A wheel and axle is a lever or a
pulley connected to a shaft.
The Inclined Plane Family
A loading ramp is another type of simple
machine, an inclined plane.
Inclined Planes Multiply and Redirect
Force
An inclined plane turns a small input force into
a large output force by spreading the work out
over a large distance.
Pushing something up a long ramp that rises
gradually is easier than pushing something up
a short, steep ramp.
A Wedge is a Modified Inclined Plane
A wedge works like 2 inclined planes back to
back.
Using a wedge is like pushing a ramp instead
of pushing an object up the ramp.
A wedge turns a single downward force into 2
forces directed out toward the sides.
Examples of wedges: nails, axe blade or log
splitting wedge
A Screw is an Inclined Plane Wrapped
Around a Cylinder
Like pushing an object up a ramp, tightening a
screw with gently sloping threads requires a
small force acting over a large distance.
Tightening a screw with steeper threads
requires more force.
Examples of screws: Jar lids, spiral staircases,
machine screws
Compound Machines
A machine made of more than one simple
machine is called a compound machine.
Examples of compound machines are:
Scissors, which use two first class levers
joined at a common fulcrum
A car jack, which uses a lever in
combination with a large screw
In-Class Assignments
In-Class Assignments:
Section 8.2 review, pg. 262, #1-4
Section 8.2 study guide
Section 8.2 Quiz
You may use your book and/or your guided
notes.
“The Pyramids” Worksheet
Read the paragraphs and answer the
questions.
Question #1 you can answer from the reading.
Question #2 Hint: 2.2 X 104 N = 22,000 N
To solve: Work = Force X Distance
Questions #3 Hint: 4.5 X 104 N = 45,000 N
9.0 X 105 J = 900,000 J
To solve: Distance = Work
Force
Inclined Plane Quick Activity
Just like we did last week with the levers, now
we will use books, etc. to test various types of
inclined planes, or ramps.
Get with your lab partner and complete the
“Inclined Plane Quick Activity” side of your
worksheet…
Looking
Ahead: Thursday will be a lab
day with 3 different activities.