module -6 eng. islam al-jarrah. module objectives identify inclined planes, wedges and screws. ...
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Eng. Islam Al-Jarrah
INCLINED PLANE, SCREWS &
WEDGES
Module -6
Eng. Islam Al-Jarrah
Module Objectives
Identify inclined planes, wedges and screws.
Describe the purpose and application of each one of them.
Calculate the mechanical advantage of inclined planes, wedges and screws.
Conduct practical tasks to demonstrate the function of inclined planes, wedges and screws.
Eng. Islam Al-Jarrah
Inclined Plane
What is an inclined plane? How do they make our work easier?
Eng. Islam Al-Jarrah
Inclined Plane
An inclined plane is a simple machine. It has a slanted (sloped) surface used to move objects to another height with less force
The advantage of using an inclined plane has been known for thousands of years -Pyramids.
Using an inclined plane to raise an object to a given height, the object must be moved a longer distance, but with less effort needed.
Eng. Islam Al-Jarrah
Inclined Planes
Click icon to add picture
A lot of effort is needed to raise a given load a short distance straight upwards, whereas much less force is needed to raise it gradually at an angle over the longer distance of an inclined plane.
Eng. Islam Al-Jarrah
Inclined Plane
Give Real Life examples on Inclined Planes?StairsRampLadder
Class Activity Page -5
Mechanical Advantage of Inclined Plane
Click icon to add picture
MA = D / HMechanical Advantage (MA) = 3m/1m = 3
Eng. Islam Al-Jarrah
Calculating the effort needed to raise a known load can be done using this formula:
Effort = Load/MA
DISTANCE Effort
Problems:
MA=D/H= 4/2= 2
Effort= Load/MA= 600/2= 300 N
MA= D/H= 6/2=3
Effort= Load/MA= 600/3= 200 N
Calculate the Mechanical advantage and the effort needed for the following inclined plane?
Calculate the Mechanical advantage and the effort needed for the following inclined plane?
Eng. Islam Al-Jarrah
2 m
he
igh
t600 N
2 m
600 N
6 m
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PRACTICAL SKILLS –INCLINED PLANE
Page 12-13
Eng. Islam Al-Jarrah
Wedges
What is a wedge? Why do we need a wedge and where?
Eng. Islam Al-Jarrah
Wedge
A wedge is a simple machine shaped like an inclined plane. Unlike an inclined plane a wedge can move.
Wedges are tools used to push two objects apart.
A wedge can have a single or two sloping surfaces.
The effort you need depends on the relationship between the length and width of the wedge and the sloping surface.
A simple device called a wedge and feather can split huge granite blocks.
Wedges
Click icon to add picture
Example from real life on wedges !!
Any more examples??
Eng. Islam Al-Jarrah
Eng. Islam Al-Jarrah
Wedges
Class Activity : Inclined or wedge?
Task1 Cut the tree Wedge
Task 2 Split the wood Wedge
Task 4 Transport logs of wood from the truck to the shop floor Inclined Plane
Mechanical Advantage of a Wedge
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Eng. Islam Al-Jarrah
The sharper the angle of the wedge, the more mechanical advantage it will have.
SHARPER MA Effort
Problems:
MA=Slope/thickness
= 35/5= 7
MA= Slope/Thickness
= 50/5 = 10
Calculate the Mechanical advantage for the following wedge?
Calculate the Mechanical Advantage for the following Wedge?
Eng. Islam Al-Jarrah
5 m
50m5 m35 m
Eng. Islam Al-Jarrah
PRACTICAL SKILLS –WEDGES
Page 14-15
Eng. Islam Al-Jarrah
Screws
What is a Screw? Why do we need a Screw and where?
Eng. Islam Al-Jarrah
Screw
A screw is a simple machine and it is a modification of an inclined plane.
The threads of a screw are like an inclined plane wrapped around a cylinder.
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Where do we use screws? Give Examples on Screws?
Different Screw TypesLampDrillCork Screw
screw-pump design to move water for irrigation by Archimedes.
ScrewsClick icon to add picture
Pitch of the screw is number of threads per cm.
Eng. Islam Al-Jarrah
Pitch = screw length/ number of threads
The finer the pitch of the screw, the more turns are required, but the less effort is needed to drive the screw in.
Finer PitchMore Threads
More Turns Less Effort
Mechanical Advantage of a Screw
Eng. Islam Al-Jarrah
Click icon to add picture
This means if you can twist your screw driver with a force of 1N you can generate a force of 4N.
Problems:
pitch=10/100= 1/10
MA= 2*pi*0.5/0.1
Calculate the Mechanical advantage for the following Screw if it is 10 cm long and has 100 threads?given that the diameter is 1 cm
Eng. Islam Al-Jarrah