View source for Apps-On-Physics/C2/Forces/English-timed

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|| '''Time'''
|| '''Narration'''
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||00:01
|| Welcome to the Spoken Tutorial on '''Forces'''.

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|| 00:06
|| In this tutorial we will, Find the resultant of forces using addition of vectors.

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|| 00:13
|| Achieve an equilibrium condition using parallelogram of forces.

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|| 00:19
|| Here I am using, 

'''Ubuntu Linux''' OS version 16.04

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|| 00:26
|| '''Firefox Web Browser''' version 62.0.3
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|| 00:31
|| To follow this tutorial, learner should be familiar with '''Apps on Physics'''.

For the pre-requisites tutorials please visit this site.

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|| 00:42
|| Use the given link to download the '''Apps'''.

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|| 00:46
|| I have already downloaded '''Apps on Physics''' to my '''Downloads''' folder.

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||00:51
||In this tutorial we will use,

'''Resultant of Forces''' and '''Equilibrium of Three Forces Apps'''.

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|| 01:00
|| Right click on '''resultant_en.htm '''file.

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|| 01:05
|| Select the option '''Open with Firefox Web Browser'''.

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|| 01:10
|| '''Resultant of Forces App''' opens.

You can open the '''App''' using any other '''browser'''.
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|| 01:18
|| This is the interface of '''Resultant of Forces'''.
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|| 01:22
|| By default, '''App''' shows two vectors drawn from a fixed point.
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|| 01:27
|| We can click and drag the vectors to change their magnitude and direction.
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|| 01:33
|| In the green control panel there is a drop-down to change the '''Number of forces'''.
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|| 01:39
|| From the drop-down we can change the values from 2 to 5.

By default 2 is selected.
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|| 01:48
|| Click on '''Find out resultant''' button.
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|| 01:51
|| Notice that the second vector translates parallel to itself.

It is attached to the head of the first vector.
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|| 02:00
|| Vectors are add using head to tail method.
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|| 02:05
|| Observe that the red vector, is the resultant vector formed by addition of two vectors.
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|| 02:12
|| It is drawn from the point of contact to the head of the second vector.

Addition of vectors follow triangle law of vectors.
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|| 02:24
|| Let us state triangle law of vector addition.

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|| 02:28
|| 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.
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|| 02:43
|| Click on '''Clear construction''' button to clear the resultant force.
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|| 02:48
|| From '''Number of forces '''drop-down select 5.
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|| 02:52
|| Click and drag the vectors to change their magnitude and direction.

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|| 02:58
|| Adjust the vectors to get equal magnitude for all vectors.
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|| 03:04
|| Then click on '''Find out resultant''' button.
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|| 03:08
|| Notice that each vector will get attached to the head of the previous vector.

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|| 03:14
|| The resultant is drawn, as its tail is joined to the tail of first vector and head to the head of last vector.
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|| 03:24
|| This represents polygon law of vector addition.
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|| 03:29
|| As an assignment 

Change the number of forces to 3 and 4.

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|| 03:35
|| In each case, change the magnitude and direction.

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|| 03:39
|| Observe the resultant vectors and explain your observation.
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|| 03:45
|| Now let us explore '''Equilibrium of Three Forces'''.
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|| 04:49
|| To open the '''App''' right-click on '''equilibriumforces_en.htm''' file.

And '''Open With Firefox Web Browser'''.
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|| 04:00
|| This is the interface of '''Equilibrium of Three Forces'''.

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|| 04:05
|| Below the name a short description about how to use interface is given.
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|| 04:11
|| The hanging weights represent the forces acting on the knot.
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|| 04:16
|| The green panel shows '''Left''', '''Right''' and '''Below''' forces.

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|| 04:22
|| These forces are acting on the knot to achieve an equilibrium condition.
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|| 04:28
|| Notice that each force must be smaller than the sum of other two forces.
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|| 04:34
|| '''App''' has measured the '''Left''' angle as 30 degrees and '''Right''' side angle as 56 degrees. 
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|| 04:44
|| Let us define equilibrium of forces.

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|| 04:47
|| When all the forces acting on an object are balanced, then the object is said to be in a state of equilibrium.
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|| 04:56
|| By default '''Parallelogram of forces''' check-box is selected.
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|| 05:01
|| If we uncheck the box, angles formed will not be seen. 
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|| 05:06
|| Press '''F5''' key on the keyboard to get the default view.
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|| 05:11
|| Let us change the forces to 6 '''newton''', 4 '''newton''', and 8 '''newton'''.
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||05:18
|| 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.

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|| 05:29
|| Similarly 8 is smaller than the sum of 6 and 4.
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|| 05:35
|| This satisfies the above balance condition.
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|| 05:39
|| We can change the position of the pulleys using the mouse.
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|| 05:44
|| Choose 4 newton for''' Left, Right''' and '''Below''' forces.
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|| 05:49
|| Notice that for equal forces the '''Angle''' is always 60 '''degrees'''.
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|| 05:55
|| Use '''F5''' button on the keyboard to refresh the '''App'''.
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|| 05:59
|| Change all the forces to 7 newton and observe the angles.
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|| 06:05
|| As an assignment - Try different combinations of forces to check the angles and equilibrium conditions.

Give an explanation.
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|| 06:18
|| Let us summarize.
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|| 06:20
|| Using these '''Apps''' we have,

Found the resultant of forces using addition of vectors.

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|| 06:28
||  Achieved an equilibrium condition using parallelogram of forces.

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|| 06:34
|| These '''Apps '''were created by '''Walter-fendt''' and his team.
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|| 06:39
|| The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it.
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|| 06:47
|| The '''Spoken Tutorial Project''' team, conducts workshops and gives certificates.

For more details, please write to us.
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|| 06:56
|| Please post your timed queries in this forum.
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|| 07:00
|| Spoken Tutorial Project is funded by MHRD, Government of India.
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|| 07:06
|| This is Himanshi Karwanje from IIT-Bombay. 
Thank you for joining.
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|}