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

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 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? Stairs Ramp Ladder  Class Activity Page -5 Eng. Islam Al-Jarrah

Mechanical Advantage of Inclined Plane MA = D / H Mechanical 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

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? Eng. Islam Al-Jarrah 2 m height 600 N 2 m 600 N 6 m

Page Eng. Islam Al-Jarrah

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. Eng. Islam Al-Jarrah

Wedges Example from real life on wedges !! Any more examples?? Eng. Islam Al-Jarrah

Wedges  Class Activity : Inclined or wedge? Eng. Islam Al-Jarrah Task1Cut the tree Wedge Task 2Split the wood Wedge Task 4 Transport logs of wood from the truck to the shop floor Inclined Plane

Mechanical Advantage of a Wedge Eng. Islam Al-Jarrah The sharper the angle of the wedge, the more mechanical advantage it will have.

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 50m 5 m 35 m

Page Eng. Islam Al-Jarrah

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. Eng. Islam Al-Jarrah

Where do we use screws?  Give Examples on Screws? Different Screw Types Lamp Drill Cork Screw  screw-pump design to move water for irrigation by Archimedes. Eng. Islam Al-Jarrah

Screws 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.

Mechanical Advantage of a Screw Eng. Islam Al-Jarrah 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