Apps-On-Physics/C2/Simple-Machines/English
Time | Narration |
Slide Number 1
Title Slide |
Welcome to this spoken tutorial on Simple Machines. |
Slide Number 2
Learning objective |
In this tutorial we will demonstrate,
Pulley system Lever Principle Apps. |
Slide Number 3
System Requirements |
Here I am using,
Ubuntu Linux OS version 16.04 Firefox Web Browser version 62.0.3 |
Slide Number 4
Pre-requisites |
To follow this tutorial, learner should be familiar with topics in school physics. |
Slide Number 5
Learning Goals |
Using these Apps we will,
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Slide Number 6
Pulley A pulley is a simple machine that is used to lift the heavy objects. We can either use a single pulley or a combination of pulleys.
wells, escalators, rock climbing, flag poles and others.
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First we will define a pulley
A pulley is a simple machine that is used to lift the heavy objects.
wells, escalators, rock climbing, flag poles and others. |
Slide Number 7
Link for Apps on physics App https://www.walter-fendt.de/html5/phen/
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Use the given link to download the Apps.
https://www.walter-fendt.de/html5/phen/
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Point to the file in the downloads folder | I have already downloaded Apps on Physics to my Downloads folder. |
Point to html5phen folder in the Downloads folder. | After downloading, html5phen folder appears in the Downloads folder.
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Double-click on html5phen folder.
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Double-click on html5phen folder.
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Double-click on phen folder.
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Now double-click on the phen folder.
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Point to the htm formats Apps. | We will use the Apps with htm file format.
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Point to Pulley system, Lever Principle Apps. | To open Pulley system press Ctrl+F keys and type Pulley system. |
Right click on pulleysystem_en.htm file.
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Right click on pulleysystem_en.htm file.
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Point to the App interface.
Move the cursor to the green panel. Move the cursor to the yellow panel. |
The App interface opens with two panels.
A green coloured panel to change and display parameters. An yellow panel with a pulley system. |
Move the cursor on the load – pulley-rope. | Here we can see that a load is attached to the pulley through a rope. |
Point to the Springscale. | We can either raise or lower the load with the help of a Springscale. |
Show the movement of the Springscale by the pressed mouse.
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Click and drag the mouse to raise or lower the load.
Observe that there is no changes in the values in the right panel. This is because the necessary force required to drag the load remains the same. |
Click on drop down list to show the numbers of pulleys | On the top of the green panel you can see a drop down list of pulleys.
List has 2, 4, and 6 pulleys systems. |
Point to the Weight.
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The weight of the load is displayed in the white box.
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Move the cursor to show the Weight of the loose pulleys. | We can change the Weight of the loose pulley in this box. |
Point to the black pulleys. | This is the toatal weight of the 4 pulleys. |
Point to show Necessary force. | Next the Necessary force used to lift the load is calculated using the App. |
Point to Springscale and Force vectors. |
At the bottom of the green panel we have Springscale and Force vectors radio buttons.
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Now let us demonstrate the working of the pulley. | |
Point to the load.
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Observe that weight of 20 N is hanging from the 4 pulley sections of the rope.
In the App the force required to raise the weight in the air is calculated. |
Slide Number 8
Necessary force F= (Wl+ Wp)/4 Wl is Weight of the load. Wp is Weight of the loose pulley. |
The Necessary force is calculated using the given formula.
F= (Wl+ Wp)/4 Wl is weight of the load. Wp is weight of the loose pulley. |
Edit the Weight of the loose pulley to 20 N.
Point to Necessary force |
Now change the Weight of the loose pulley to 20 N.
Observe that the Necessary force is changed to be 10 N. |
Change the Weight of the load to 30 N. | Next change the weight of the load to 30 N. |
Point to the Weight of the loose pulley.
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Note that as we change the weight of the load to 30 N, weight of the loose pulley has changed to 10 N.
Values more than 10 N are automatically changed to 10 N. |
Slide Number 9
Assignment Change the weight of the load to 25 N and weight of the loose pulley to 10 N and calculate the necessary force. Verify your answer from the App.
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As an assignment,
Change the weight of the load to 25 N and Weight of the loose pulley to 10 N and calculate the necessary force. Verify your answer from the App.
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To open lever principle App right-click on lever_en.htm and Open With Firefox Web Browser. | Next we will move on to Lever Principle App.
To open lever principle App right-click on lever_en.htm and Open With Firefox Web Browser. |
Point to the screen(highlight the sentence from the App.) | This app shows a symmetrical lever with some mass pieces.
Each mass piece weighs 1 N. |
Scroll down to show the lever principle.(pink box) | At the bottom of the interface Lever Principle is defined.
A lever is in balance if the total left side torque is equal to the total right side torque. |
Scroll up to see the App.
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Observe that the lever arm is shown by green and yellow rectangles.
Length of each rectangle is 0.10 m. |
Point to the torque measured. | At left bottom of the screen torque is calculated. |
Slide Number 10
Torque Torque is the twisting force that tends to cause a rotation. The point where the object rotates is aixs of rotation. |
Torque is the twisting force that tends to cause rotation.
The point where the object rotates is the axis of rotation. |
Point to the fulcrum. | In the App fulcrum is the axis of rotation. |
Slide Number 11
Torque (tau) τ = F r⟂ F is a force applied by the load. r⟂ is a perpendicular distance from the fulcrum. |
Next we can calculate the torque using the formula.
(tau)τ = F* r⟂(perpendicular) .
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Point to green and yellow rectangles. | The green and yellow rectangles indicate perpendicular distances. |
Remove one weight from the left side of the fulcrum. | We can change the hanging weight by clicking and holding mouse. |
Point to fulcrum.
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Observe that now the lever is unbalanced.
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Point to 0.9 Nm. | Notice that in the measured part the value of left side torque is reduced to 0.9 Nm
(Newton-meter). |
Slide Number 12
Assignment What happens when hanging weights are removed from both the sides. |
What happens when hanging weights are removed from both the sides. |
Point to the left side of the fulcrum. | Next let us hang the weights at different distances to the left of the fulcrum. |
Click and hold the mouse to add one weight on the third rectangle.
Continue to add two weights on the fourth rectangle. One weight on the fifth rectangle. |
Click and hold the mouse to add one weight on the third rectangle.
Add two weights on the fourth rectangle. And one weight on the fifth rectangle. |
Point to the lever. | Observe that the lever is now unbalanced. |
Point to the right side. | Now let us add weights to the right side to balance the lever. |
Use pressed mouse to add the weights from
right to 1st rectangle. |
Click and hold the mouse to add one weight to the first rectangle. |
Hang the weight to 3rd, 4th, and 5th rectangles. | Continue to add one weight to third, fourth and fifth rectangles. |
Point to the lever. | Notice that the lever is now balanced. |
Slide Number 13
Assignment If a blocks weigh 5 N is kept at 0.5 m, 3 N at 0.4 m and 2 N at 0.6 m from the fulcrum on the same side. How far must the other blocks of weighs 7 N should kept from the fulcrum in order to balance them. |
As an assignment solve this numerical.
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Let us summarise | |
Slide Number 18
Summary |
Using these App we have * Observed how a pulley system works.
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Slide Number 19
License These Apps are created by Walter-fendt and his team. This video is released under CC-BY-NC-SA license.
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These Apps are created by Walter-fendt and his team.
This video is released under CC-BY-NC-SA license.
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Slide Number 19 About Spoken Tutorial project.
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The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
Slide Number 20
Spoken Tutorial workshops.
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Spoken Tutorial Project team,
conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us. |
Slide Number 21
Forum for specific questions:
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Do you have questions in THIS Spoken Tutorial?
Please visit this site Choose the minute and second where you have the question. Explain your question briefly Someone from our team will answer them |
Slide Number 22
Forum for specific questions:
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The Spoken Tutorial forum is for specific questions on this tutorial
Please do not post unrelated and general questions on them This will help reduce the clutter Template:Anchor With less clutter, we can use these discussion as instructional material. |
Slide Number 23
Acknowledgement |
Spoken Tutorial Project is funded by MHRD, Government of India. |
This is Himanshi Karwanje from IIT-Bombay.
Thank you for joining. |