Post on 27-Dec-2015
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What’s MyWhat’s MyMeaning?Meaning?
GearingGearingUpUp
PulleyPulleyPowerPower
Real LifeReal LifeExamplesExamples
What’s the What’s the Advantage?Advantage?
What is mechanical advantage?
Mechanical advantage is the amount
of help that a machine
gives you.
Describe how we can turn something to make
something else turn.
When a gear turns it forces the meshed gear to turn
as well.
How can a gear turn to make something
else go straight?
Rack and pinion transfers motion from a rotation to a
straight line
What is a PULLEY?
A pulley is a simple machine.
It is made with a grooved wheel and a
rope.
What is a GEAR?
DAILY QUADRUPLE
A gear is a simple machine. It is a toothed wheel that meshes another toothed mechanism.
It can change the speed, direction, or amount of force needed to do work.
When the teeth of two gears are in
contact with each other they are…
Meshed
How can a pulley change
the type of motion?
A pulley can transfer/change a downward motion to an
upward motion (lifting up to
pulling down)
What would a gear system look like that speeds up
motion?
Turn the first gear to make the second go
faster (second has fewer teeth so it rotates
faster)
Rotate B to make A go
fast
Driver
Follower
?
What direction is the follower gear moving in?
Counter-clockwise
Driver
Follower
Identify the following:
•Gear•Teeth•Axle•Meshed Area
This is an example of what type of pulley system?
A Movable Pulley System
A movable pulley is a pulley that moves with the load.
•The advantage of a movable pulley is that the effort needed to move the load is less than the weight of the load.•The disadvantage is that the load is moving in the same direction as the effort and this is not always convenient.
This is an example of what type of pulley system?
A Fixed Pulley System
The fixed pulley is attached to an unmovable object.
•The advantage is that the direction of the effort needed to move the load is opposite to the load itself. •The disadvantage is that you have to apply the same effort to lift the load as the weight of the load.
Identify a pulley system that we use
in our daily life
Pulley Systems
FlagpoleClotheslineCraneElevatorEtc.
What type of pulley system does NOT give you
mechanical advantage?
A Fixed Pulley System
What is the effort needed to
lift a load of 120N using this pulley system?
(all movable pulleys)
30 Newtons
Match the following:
Fixed Pulley
Movable Pulley
Block and Tackle Pulley
A
B
C
1
2
3
Match the following:
Fixed Pulley
Movable Pulley
Block and Tackle Pulley
A
B
C
3
2
1
Worm Gear
Bevel Gear
Spur GearA
B
C
1
2
3
Match the following:
Worm Gear
Bevel Gear
Spur GearA
B
C
1
2
3
What is different about the way gears on a bicycle turn in comparison to standard spur
gears?
Bicycles have sprocket and chain gears that work like some pulley systems. A chain connects the
sprocket gears on the pedals to the back wheel. The chain also allows the gears to turn in the same
direction. The sprockets keep the chain from slipping as it turns.
The gears turn in the same direction.
Identify some gear systems that are used in daily life.
Gear Systems;
Clocks
Bicycles
Hand drills
Transmissions
Etc.
How does a bicycle work?
-The rider turns the pedals (input: force used to make the system work) which are attached to gears
- The gear has a chain around it attached to the gear at the back wheel
-The chain forces the back gear to turn
-The back gear is attached to the wheel so when it turns it forces the wheel to turn (output: what happens as a result of the input)
How many times would the follower gear rotate if the
driver gear were to rotate 2 times?
FOLLOWER
DRIVER
4 Times.
This is an example of gearing up.
FOLLOWER
DRIVER
DAILY TRIPLE
How many times would the driven gear rotate if the driver gear were to rotate 3 times?
FOLLOWER
DRIVER
1 Time.
This is an example of
gearing down.
FOLLOWER
DRIVER
What is the effort needed to
lift a load of 50N using this pulley system?
25 Newtons
What is the effort needed to
lift a load of 400N using this pulley system?
200 Newtons
Fill in the blanks:1. A gear train can change the
_______, _______, or amount of _______needed to do work.
2. A pulley system can change the _______ of effort and the _______ of effort needed to move a load.
1. A gear train can change the speed, direction or amount of effort needed to do work.
2. A pulley system can change the amount of effort and the direction of effort needed to move a load.