# Difference between revisions of "Apps-On-Physics/C2/Simple-Machines/English"

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 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 basic physics. Slide Number 5 Learning Goals Using these Apps we will, Show how a pulley system works. Calculate the necessary force to pull the load. Show the working of a lever. Explain how to achieve a balance condition. Slide Number 6 Pulley A pulley is a simple machine that is used to lift heavy objects. We can either use a single pulley or a combination of pulleys. For example pulleys can be used in wells, escalators, rock climbing, flag poles and others. First we will define a pulley A pulley is a simple machine that is used to lift heavy objects. We can either use a single pulley or a combination of pulleys. For example pulleys can be used in wells, escalators, rock climbing, flag poles and others. Slide Number 7 Link for Apps on physics . Use the given link to download the Apps. 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. Double-click on html5phen folder. Point to the ph and phen folders. Double-click on html5phen folder. We see two folders namely ph and phen . Double-click on phen folder. Point to Apps in java script and htm format. Now double-click on the phen folder. In this folder, we see Apps in java script and htm format. Point to the htm formats Apps. We will use the Apps with htm file format. Point to Pulley system App. To open the Pulley system app press Ctrl+F keys simultaneously. In the search bar type Pulley system. Right click on pulleysystem_en.htm file. Select the option Open With Firefox web Browser option. Cursor on the App. Right click on pulleysystem_en.htm file. Select the option Open With Firefox web Browser. Pulley System App opens in the browser. Point to the App interface. Move the cursor to the yellow panel. Move the cursor to the green panel. The App interface opens with two panels. A yellow panel with a pulley system and A green panel to change and display parameters. Move the cursor on the load – pulley-rope. In the yellow panel, notice that a load is attached to the pulley with the help of a rope. Point to the Springscale. We can either raise or lower the load using a Springscale. Show the movement of the Springscale by the pressed mouse. Point to the values in the right panel. Click and drag the mouse to raise or lower the load. Observe that there is no change in the value 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 pulley systems. Point to the Weight. Edit and show 1 value (write 20) The weight of the load is displayed in the white box. The default weight of the load is 14 Newton. We can change the value of the weight from 1 Newton to 40 Newton. 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 total weight of the 4 pulleys. Point to show Necessary force. 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. By default Springscale is selected. Let us demonstrate the working of the pulley. Point to the load. Point to the 4 sections of the rope. Point to Necessary force. Observe that weight of 20 Newton is hanging from the 4 pulley sections of the rope. Each section of the rope has one fourth of the total weight. In the App force required to raise the weight in 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 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 Newton. Point to Necessary force Now change the Weight of the loose pulley to 20 Newton. Observe that the Necessary force is changed to 10 Newton. Change the Weight of the load to 30 Newton. Next change the weight of the load to 30 Newton. Point to the Weight of the loose pulley. Highlight the last line from the App. observe that the weight of the loose pulley has changed to 10 Newton. This is because the Springscale’s limit is 10 Newton. Values more than 10 Newton are automatically changed. Slide Number 9 Assignment Change the weight of the load to 25 N and weight of the loose pulley to 10 N. Calculate the necessary force and verify your answer from the App. As an assignment, Change the weight of the load to 25 N and Weight of the loose pulley to 10 N. Calculate the necessary force and verify your answer from the App. To open Lever Principle App right-click on lever_en.htm file 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 file 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 Newton. 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. Point to the lever arm. Observe that the lever arm is shown by green and orange rectangles. Length of each rectangle is 0.10 m. Point to the torque measured. At the bottom left 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 a 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. We can calculate the torque using the formula. (tau)τ = F* r⟂(perpendicular) . Point to green and orange rectangles. Green and orange rectangles indicate perpendicular distances. Remove one weight from the left side of the fulcrum. We can change the hanging weight by clicking and holding the mouse. Point to fulcrum. Move the cursor to show the calculations. Observe that, the lever is unbalanced. This is because torque on both the sides is not same. Point to 0.9 Nm. Notice that the value of left side torque is reduced to 0.9 Nm (Newton-meter). In the text-box type. (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. 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. 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. Let us add weights to the right side of the fulcrum 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 weights to third, fourth and fifth rectangles. Point to the lever. Notice that the lever is now balanced. Slide Number 12 Assignment On the same side of the fulcrum, if a block weighing 5 N is kept at 0.5 m and a block weighing 3 N is kept at 0.6 m, then how far a block weighing 7 N should be kept on the other side of the fulcrum to achieve a balance condition. As an assignment solve this numerical. Let us summarize Slide Number 13 Summary Using these Apps we have Observed how a pulley system works. Calculated the necessary force to pull the load. Observed the working of a lever. Explained how to achieve a balance condition. Slide Number 14 License These Apps are created by Walter-fendt and his team. These Apps are released under CC-BY-NC-SA license. These Apps are created by Walter-fendt and his team. These Apps are released under CC-BY-NC-SA license. Slide Number 15 About Spoken Tutorial project. The video at the following link summarizes the Spoken Tutorial project. Please download and watch it. The video at the following link summarizes the Spoken Tutorial project. Please download and watch it. Slide Number 16 Spoken Tutorial workshops. Spoken Tutorial Project team, conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us. 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 17 Forum for specific questions: 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. 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 18 Forum for specific questions: 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 With less clutter, we can use these discussion as instructional material 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 With less clutter, we can use these discussion as instructional material. Slide Number 19 Acknowledgement Spoken Tutorial Project is funded by MHRD, Government of India. This is Himanshi Karwanje from IIT-Bombay. Thank you for joining.