Apps-On-Physics/C2/Forces/English

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Visual Cue Narration
Slide Number 1

Title Slide

Welcome to the Spoken Tutorial on Forces.
Slide Number 2

Learning Objectives

In this tutorial we will,

Find the resultant of forces using addition of vectors.

Achieve an equilibrium condition using parallelogram of forces.

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-requities

https://spoken-tutorial.org/

To follow this tutorial, learner should be familiar with Apps on Physics.

For the pre-requisites tutorials please visit this site.

Slide Number 5

Link for Apps on physics simulation https://www.walter-fendt.de/html5/phen/

Use the given link to download the Apps.

https://www.walter-fendt.de/html5/phen/

Point to the file in the Downloads folder. I have already downloaded Apps on Physics to my Downloads folder.
Slide Number 6

Apps on Physics

In this tutorial we will use,

Resultant of Forces and Equilibrium of Three Forces Apps.

Right click on resultant_en.htm file.

Select option Open With Firefox Web Browser option.

Right click on resultant_en.htm file.

Select the option Open with Firefox Web Browser.

Resultant of Forces App opens.

You can open the App using any other browser.

Point to the interface. This is the interface of Resultant of Forces.
Point to the vectors. By default, App shows two vectors drawn from a fixed point.
Click and drag the vectors and show the changes in magnitude and directions. We can click and drag the vectors to change their magnitude and direction.
Point to Number of forces. In the green control panel there is a drop-down to change the Number of forces.
Click on the drop down. From the drop-down we can change the values from 2 to 5.

By default 2 is selected.

Click on Find out resultant button. Click on Find out resultant button.
Point to the blue vector that shifts parallel in the right upward direction. Notice that the second vector translates parallel to itself.


It is attached to the head of the first vector.

Point to head to tail position. Vectors are add using head to tail method.
Point to the red vector.

Point to show the formation of resultant.

Observe that the red vector, is the resultant vector formed by addition of two vectors.


It is drawn from the point of contact to the head of the second vector.

Addition of vectors follow triangle law of vectors.

Slide Number 7

Triangle Law of Vector Addition

It states that, when two vectors are represented by two sides of a triangle with same magnitude

and direction then the third side represents the resultant of vectors.

Let us state triangle law of vector addition.

It states that,

  • when two vectors are represented by two sides of a triangle with same magnitude and direction
  • then the third side represents the resultant of vectors.
Click on Clear construction. Click on Clear construction button to clear the resultant force.
Click on the drop down list and select 5. From Number of forces drop-down select 5.
Click, drag and show the change in magnitude and direction.

Drag the to show equal magnitude.

Click and drag the vectors to change their magnitude and direction.

Adjust the vectors to get equal magnitude for all vectors.

Click on Find out resultant. Then click on Find out resultant button.
Point to the vector as they join to other vectors. Notice that each vector will get attached to the head of the previous vector.


The resultant is drawn, as its tail is joined to the tail of first vector and head to the head of last vector.

Cursor on the interface. This represents polygon law of vector addition.
Slide Number 8

Assignment

  • Change the number of forces to 3 and 4.
  • In each case, change the magnitude and direction.
  • Observe the resultant vectors and explain your observation.
As an assignment
  • Change the number of forces to 3 and 4.
  • In each case, change the magnitude and direction.
  • Observe the resultant vectors and explain your observation.
Cursor on the interface. Now let us explore Equilibrium of Three Forces.
To open the simulation right-click on equilibriumforces_en.htm file

and Open With Firefox Web Browser.

To open the App right-click on equilibriumforces_en.htm file.

And Open With Firefox Web Browser.

Point to the interface. This is the interface of Equilibrium of Three Forces.


Below the name a short description about how to use interface is given.

Point to the hanging weights. The hanging weights represent the forces acting on the knot.
Point to the Forces in the green Panel.

Point to the knot.

The green panel shows Left, Right and Below forces.


These forces are acting on the knot to achieve an equilibrium condition.

Highlight the sentence from the simulation.

Point to the forces.

Notice that each force must be smaller than the sum of other two forces.
Point to the Angles in the green control panel. App has measured the Left angle as 30 degrees and Right side angle as 56 degrees.
Slide Number 9

Equilibrium of Forces

When all the forces acting on an object are balanced,

then the object is said to be in a state of equilibrium.

Rightward force = Leftward force

upward force = downward force

Let us define equilibrium of forces.

When all the forces acting on an object are balanced,

then the object is said to be in a state of equilibrium.

Point Parallelogram of forces check-box. By default Parallelogram of forces check-box is selected.
Uncheck the Parallelogram of forces check-box. If we uncheck the box, angles formed will not be seen.
Press F5 key on the keyboard. Press F5 key on the keyboard to get the default view.
Change the forces to 6, 4 and 8. Let us change the forces to 6 newton, 4 newton, and 8 newton.
6< 8+4

8< 6 + 4

4< 6 + 8

Note that 6 is smaller than the sum of 8 and 4.

And note that 4 is smaller than the sum of 6 and 8.

Similarly 8 is smaller than the sum of 6 and 4.

Point to above text box. This satisfies the above balance condition.
Drag the pulley and show the movements. We can change the position of the pulleys using the mouse.
Change the value of Forces of Left, Right and Below to 4N. Choose 4 newton for Left, Right and Below forces.
Point to the angles. Notice that for equal forces the Angle is always 60 degrees.
Press F5 button of the keyboard to refresh the App. Use F5 button on the keyboard to refresh the App.
Edit the values to 7 N in all three forces and point to the angles. Change all the forces to 7 newton and observe the angles.
Slide Number 10

Assignment

Try different combinations of forces to check the angles and equilibrium conditions.

Give an explanation.

As an assignment -

Try different combinations of forces to check the angles and equilibrium conditions.

Give an explanation.

Let us summarize.
Slide Number 11

Summary

Using these Apps we have,
  • Found the resultant of forces using addition of vectors.
  • Achieved an equilibrium condition using parallelogram of forces.
Slide Number 12

Acknowledgement

These Apps were created by Walter-fendt and his team.

These Apps were created by Walter-fendt and his team.
Slide Number 13

About Spoken Tutorial project.

The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

Slide Number 14

Spoken Tutorial workshops.

The Spoken Tutorial Project team,

conducts workshops and gives certificates.

For more details, please write to us.

Slide Number 15

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

Please post your timed queries in this forum.
Slide Number 16

Acknowledgements

Spoken Tutorial Project is funded by MHRD, Government of India.
This is Himanshi Karwanje from IIT-Bombay.

Thank you for joining.

Contributors and Content Editors

Karwanjehimanshi95, Madhurig, Nancyvarkey