Apps-On-Physics/C2/Circular-motion/English
| Visual Cue | Narration |
| Slide Number 1
Title Slide |
Welcome to this tutorial on Circular Motion. |
| Slide Number 2
Learning objective |
In this tutorial we will demonstrate,
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| Slide Number 3
System Requirements |
Here I am using,
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| Slide Number 4
Pre-requities |
To follow this tutorial learner should be familiar with Apps on Physics.
For the pre-requisite tutorials please visit this site. |
| Slide Number 5
Learning Goals |
Using these Apps we will,
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| Slide Number 6
Uniform Circular Motion It is a motion of an object on a circular path with a constant speed. Example: Moon, revolves around the earth in uniform circular motion. |
Let us first define uniform circular motion.
It is a motion of an object on a circular path with a constant speed. For example: Moon, revolves around the earth in uniform circular motion. |
| Slide Number 7
Link for Apps on physics. |
Use the given link to download the Apps on Physics. |
| Open the Downloads folder. | I have already downloaded the Apps on Physics to my Downloads folder. |
| Right click on circularmotion_en.htm file.
Select the option Open With Firefox web Browser option. Cursor on the App. |
Right-click on circularmotion_en.htm file.
Select the option Open With Firefox Web Browser. Uniform Circular Motion app opens in the browser. |
| Point to the white point. | The interface shows a white coloured point on a circular path.
This white coloured point behaves as an object on a circular path. |
| Scroll down to see the App completely. | Scroll down to see the complete interface. |
| Point to the graph. | Next to the circular path, we see a graph.
This graph shows the change in position of the object with time. |
| Click on the Start button in the green control panel. | Click on the Start button. |
| Click on the Slow motion check-box. | Click on the Slow motion check-box to see the motion steadily. |
| Point to bold red vector and then the other two vectors on x and y axis. | The bold red vector shows the instantaneous position of the point.
The other two red vectors show the position of the point along the x and y axis. |
| Click on Slow motion check-box. | Uncheck the Slow motion check-box. |
| Click on the Reset button. | Click on the Reset button to reset the App. |
| Point to the red dots on the graph. | The initial position of the white point is 2 metre on x-axis and 0 metre on y-axis. |
| Point to the red vector. | This is because the white point is on the circle that has a radius of 2 metre.
And it is pointing in the positive x-axis. |
| Point to the radio button.
Click on the Velocity radio button. |
Click on the Velocity radio button. |
| Point to the pink vector. | Observe that the direction of the velocity vector is tangential to the circular path. |
| Click on Start button. | Click on the Start button and observe the change in direction of velocity. |
| Point to the velocity vector. | Notice that the magnitude of the velocity is same but its direction changes continuously. |
| Point to the y-axis. | Observe that the representation on the y-axis has changed to velocity. |
| Point to the name of y-axis. | In the graph y-axis has changed from x, y to Vx , Vy. |
| Click on the Reset button. | Click on the Reset button. |
| Point to angular velocity.
Point to the value |
Above the linear velocity the App has shown Angular velocity, denoted by omega.
The value of omega is 1.26 radians per second. |
| Click on the Start button. | Click on the Start button. |
| Select Slow motion check-box. | Select Slow motion check-box. |
| Point to the bold Pink colour vector | Here the bold pink vector shows the magnitude and direction of velocity. |
| Point to other faint x and y coordinates. | The other two vectors show the magnitude and direction on the x and y coordinates. |
| Uncheck the Slow motion check-box. | Uncheck the Slow motion check box. |
| Make a png for the formula and display on the interface.
ω=v/r ω = angular velocity v= linear velocity r = radius |
We can calculate angular velocity using the formula.
ω=v/r where ω is angular velocity v is linear velocity and r is radius of the circle |
| Click on the Reset button. | Click on the Reset button. |
| Press Enter after changing every value.
Change Radius to 5 metre, Period to 10 sand Mass to 10 Kg. |
Change the Radius to 5 metre,
Period to 10 seconds and Mass of the object to 10 kg. Press Enter after changing every value. |
| Show a png
ω=v/r =3.14/ 5 = 0.628 rad/s |
I have already calculated the value of angular velocity. |
| Point to the value. | The value of angular velocity is 0.628 rad/s (radians per second). |
| Point to the measured value of Angular velocity by the App. | The calculated value is same as the value shown in the App. |
| Click on Acceleration radio button. | Click on the Acceleration radio button. |
| Point to blue vector as centripetal acceleration. | Here the blue vector shows the direction of acceleration.
This acceleration is centripetal acceleration. |
| Point to a=1.97 m/s2. | The magnitude of acceleration is 1.97 metre per second square. |
| Point to the blue arrow. | The direction of acceleration is towards the center of the circle. |
| Make a png to show the formula on the interface. [ac=ω2r]
Click on Velocity radio button. |
This is the formula to calculate centripetal acceleration.
Click on Velocity radio button. |
| Show the angular velocity value and radius. | Substitute the values of angular velocity and radius into the formula. |
| Click on Acceleration radio button.
Show a png ac=ω2r =(0.628)2 x 5 =1.97 m/s2 |
Again click on Acceleration radio button.
Here is the calculated value of centripetal acceleration. Observe that the calculated value is same as the one shown in the App. |
| Click Force radio button. | Click on the Force radio button. |
| Point to the Force vector. | Note that the direction of Force vector is same as that of the Acceleration vector. |
| F directly proportional to acceleration. | Recall from Newton's second law that force and acceleration are directly related to each other. |
| Click on the Start button. | Click on the Start button. |
| Point to the force vector. | Force acting on a circular field is a centripetal force. |
| Point to the vector that is directed towards the center. | This force is always directed towards the center. |
| Click on the Reset button. | Click on the Reset button. |
| Slide Number 8
Numerical Consider the white point as a toy car of mass 1 Kg that moves on a circular track of radius 5.00 m in 10.0 seconds. Calculate the centripetal acceleration of the car. |
Let us solve a numerical to find centripetal acceleration.
Please pause the video and read the numerical. |
| Edit the values of Radius to 8 m and Period to 10 sec. | Then change the parameters according to the numerical. |
| Cursor on the interface. | Details about all calculations are shown in the additional material. |
| Cursor on the interface. | For now I will calculate centripetal acceleration using the formula. |
| Click on Velocity radio button. | Click on Velocity radio button. |
| Make a text-box to show the calculation.
ac=ω2r = (0.628 )2 x 8 = 3.15 m/s2 |
Let us substitute the values of angular velocity and radius into the formula.
The calculated value of centripetal acceleration is 3.15 metre per second square. |
| Click on Acceleration radio button. | Click on the Acceleration radio button to compare the value. |
| Point to the value of Acceleration. | Observe that the values are comparable. |
| Slide Number 9
Assignment A particle of mass 0.2 kg moves on a circle of radius 2 m in a time period of 10 s. Find the angular velocity. |
As an assignment solve the following numericals by changing the parameters. |
| Slide Number 10
Assignment A toy car of mass 2 Kg moves on a circle of radius 10 m. In a time period of 10 s. Find the values of angular velocity and centripetal force. |
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| Let us move on to Carousel App. | |
| html5phen<< phen<<carousel_en.htm
<<right click on the file name<< open with firefox web browser. |
To open the App right-click on carousel_en.htm file and Open With Firefox Web Browser. |
| Cursor on the interface. | Model of a Carousel App opens in the browser.
Below the name a short description about the interface is given. |
| Scroll down to see the interface. | Let us scroll down to see the interface. |
| Cursor on the interface. | This App shows the application of centripetal force. |
| Point to the attached pendulums. | Notice that eight pendulums are attached to the carousel. |
| Point to Carousel radio button. | Here we have four radio buttons.
By default Carousel is selected. |
| Make a box while editing and Point to the text-fields. | In the green panel we can change the values of the text-fields. |
| Edit the value for Period as 2.
point to the movement of the carousel. |
Let us change the Period to 2 seconds and press Enter.
Notice that the speed of the carousel has increased. Due to increase in speed radius of the axis of rotation increases. |
| Point to the pendulums. | The pendulums move away from the center. |
| Click on the Numerical values radio button. | Click on the Numerical values radio button. |
| Point to the values. | Here we can see different parameters that App has calculated. |
| Point to the value of Velocity. | The value of Velocity is 5.21 metre per second. |
| Point the values of Frequency, Angular velocity, and Centripetal force. | Note the values of Frequency, Angular velocity, and Centripetal force. |
| Change Period to 5 seconds. | Let us increase the Period to 5 seconds. |
| Point to the Frequency, Angular velocity, and Centripetal force. | As we increase the Period, Frequency, Angular velocity
and Centripetal force have decreased. |
| Click on the Carousel radio button. | Click on the Carousel radio button. |
| Point to the carousel. | Observe that the carousel speed has slowed down. |
| Change Distance between suspensions and axis of rotation to 1 metre. | Let’s change Distance between suspensions and axis of rotation to 1 metre. |
| Point to Distance between suspensions and axis of rotation. | Distance between suspensions and axis of rotation can be changed from 0 to 1 metre. |
| Point to the carousel. | Observe that the size of the carousel has increased. |
| Change the Distance between suspensions and axis of rotation to 0.3 metre. | Let’s decrease Distance between suspensions and axis of rotation to 0.3 metre. |
| Point to the carousel. | Note the decrease in the size of the carousel. |
| Point to the Length of the string. | Change the Length of the string to 0.5 metre and observe the changes on the carousel. |
| Point to the Length of the string. | Note that we can vary the Length of the string between 0 to 1 metre. |
| Change the Mass to 0.1 kg and then to 10 kg to show the change. | Similarly we can vary the Mass between 0.1 to 10 kg. |
| Click on F5 key on the keyboard to Reset. | Click on F5 key on the keyboard to Reset the App. |
| Click on Carousel with forces radio button. | Click on the Carousel with forces radio button. |
| Point to the vectors. | Here it shows three force vectors. |
| Change the value of Period to 2 seconds . | Let us change Period to 2 seconds to see the vectors clearly. |
| Click on the Pause button. | Click on the Pause button. |
| Point to black vector.
Point to blue vector. Point to red vector. |
Black vector shows the force due to the weight.
Blue vector shows the force exerted by the string And red vector is the net force pointing inward. |
| Select Sketch radio button. | To get a clear view of the vectors let us select Sketch radio button. |
| Point to the interface. | Here we can see a 2D view of the force vectors. |
| Click on Carousel radio button. | Click on Carousel radio button. |
| Click on the Resume button. | Click on the Resume button. |
| Slide Number 11
Numerical The toy horse suspended to a carousel has a mass of 1.5 kg. It moves on a circular base with a period of 4 s. If its distance between the suspension and axis of rotation is 1 m, calculate centripetal force. |
Let us solve a numerical by varying the parameters in the App.
Please pause the video and read the numerical. |
| Change and point to show the values. | Let us change the values according to the numerical. |
| Make png to show the formula on the interface.
Fc= mv2/r |
To calculate the centripetal force we can use the formula :
Fc= mv2/r |
| Click on Numerical values radio button. | Click on the Numerical values radio button. |
| Point to show the value of radius and velocity. | From here we will take the values of radius and velocity. |
| Now calculate the value of centripetal force. | |
| Show it on a text-box.
Fc= mv2/r = 1.5 x 2.06 x 2.06 1.31 = 4.85 N |
Substitute the values into the formula.
We get the value of centripetal force as 4.85 Newton. |
| Point to the values side by side. | Observe that the values are comparable. |
| Slide Number 12
Assignment The toy horse suspended to a carousel has a mass of 5 kg, it moves on a circular base with a period of 3 s. If its distance between the suspension and axis of rotation is 0.5 m, calculate angular velocity, angular acceleration and centripetal force. |
As an assignment solve the given numerical. |
| Let us summarise | |
| Slide Number 13
Summary |
Using these Apps we have,
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| Slide Number 14
Acknowledgement These Apps were created by Walter-fendt and his team. |
These Apps were created by Walter-fendt and his team. |
| Slide Number 15
About Spoken Tutorial project. |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
| Slide Number 16
Spoken Tutorial workshops. |
The Spoken Tutorial Project team,
conducts workshops and gives certificates. For more information, 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. |
Please post your timed queries on this forum. |
| Slide Number 18
Acknowledgement |
Spoken Tutorial Project is funded by MHRD Government of India. |
| This is Himanshi Karwanje from IIT-Bombay.
Thank you for joining. |
