View source for PhET-Simulations-for-Physics/C3/Projectile-Motion/English-timed

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|'''Time'''   
|'''Narration'''   

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|| 00:01
|| Welcome to this tutorial on '''Projectile motion'''. 

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|| 00:05
|| In this tutorial, we will demonstrate '''Projectile Motion PhET simulation'''. 

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||00:11
|| To follow this tutorial, learner should be familiar with topics in high-school physics. 

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||00:18
|| Here I am using: 

'''Ubuntu Linux OS''' version 14.04, 

'''Java''' version 1.7, 

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|| 00:26
||'''Firefox Web Browser''' version 53.02.2. 

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|| 00:31
|| Using this simulation, we will- 
1. Determine how each parameter affects the trajectory of an object. 

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|| 00:39
||2. Estimate where an object will land, given its initial conditions. 

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|| 00:45
||3. Determine how horizontal and vertical motion of a projectile are independent. 

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||  00:51
||4. Investigate the variables that affect the drag force. 

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|| 00:56
||5. Examine the effect of drag force on the velocity and acceleration. 

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|| 01:02
|| Let us define a projectile. 

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|| 01:05
||A projectile is any object that is fired, pitched or thrown. 

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|| 01:11
||The path of the projectile is called its trajectory. 

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|| 01:15
|| Projectile motion is a form of motion in which a projectile is thrown near the Earth's surface. 

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|| 01:22
|| A projectile moves along a curved path under the action of gravity. 

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|| 01:27
||Gravity is the downward force acting on a projectile. 

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|| 01:32
||Gravity influences its vertical motion and causes the parabolic trajectory. 

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|| 01:39
|| Some examples of projectile motion are-  A baseball that has been thrown. 

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|| 01:46
||A bullet that is fired from a gun or rifle. 

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|| 01:51
|| Use the given '''link''' to download the simulation. 
 
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|| 01:55
|| I have already downloaded '''Projectile Motion PhET simulation''' to my '''Downloads''' folder. 

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|| 02:02
|| To open the simulation, right click on '''projectile-motion_en.html''' file. 

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|| 02:10
||Select the option '''Open With Firefox Web Browser'''. 

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|| 02:15
|| This is the interface of '''Projectile Motion PhET simulation'''. 

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||02:20
|| The interface has four screens: 

'''Intro''', 

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|| 02:25
||'''Vectors''', 

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|| 02:27
||'''Drag ''', 

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|| 02:29
||'''Lab'''. 

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|| 02:31
|| Click on '''Intro''' screen. 

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|| 02:34
||Using this screen, let's study the factors affecting a projectile’s trajectory. 

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|| 02:40
|| '''Intro''' screen has a  cannon mounted on a  pedestal.

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|| 02:45
|| Default height of the pedestal is 10 m. 

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|| 02:49
||'''Height label''' disappears when height is adjusted. 

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|| 02:53
||We can change the height of the pedestal between 0 to 15 m. 

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|| 02:59
|| Click on '''Reset''' button to '''reset''' the simulation. 

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|| 03:03
|| By default, cannon's angle is at 0 degrees. 

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|| 03:08
||Cannon's angle can be changed from minus 90 degrees to 90 degrees(-90 to 90). 

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|| 03:14
||Drag Cannon's angle to zero degrees. 

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|| 03:18
|| At the bottom of the screen, we have: a slider to change '''Initial Speed''', 

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|| 03:23
|| yellow '''Eraser''' icon to erase the trajectory, 

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|| 03:27
|| red '''Launch Projectile''' icon to launch the '''projectile''', 

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|| 03:32
|| '''Play/Pause '''and '''Step '''buttons, 

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|| 03:36
|| '''Normal '''and ''' Slow''' radio-buttons to change '''animation''' speed. 

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|| 03:41
|| At the top left corner, we have ''' Zoom in''' and '''Zoom out ''' buttons to '''zoom''' the view. 

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|| 03:48
|| On the top right corner, we have a white box.  It contains a '''probe''' and a measuring tape.

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|| 03:56
|| Probe is used to measure '''Time''', '''Range''' and '''Height''' of the trajectory. 

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|| 04:02
|| A drop down list is provided to select the projectiles. 

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|| 04:06
||By default, '''Pumpkin''' is selected as a projectile. 

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|| 04:10
|| '''Mass''' and '''Diameter''' of the selected projectile is displayed below the list. 

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|| 04:16
|| Next we have a check box to introduce '''Air Resistance''' with''' Drag Coefficient'''. 

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|| 04:22
|| Then we have '''Velocity Vectors''' and '''Acceleration Vectors ''' check boxes. 

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|| 04:28
|| Let us select '''Human''' projectile from the list. Observe the displayed '''Mass '''and '''Diameter''' of the '''Human projectile.''' 

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||  04:38
|| Click on red''' Launch''' icon. Observe the trajectory. 

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|| 04:44
|| Next we will change cannon's angle to 10 degrees. 

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|| 04:49
||Launch the projectile. 

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|| 04:54
|| Observe projectile's trajectory as we change cannon's angle. 

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|| 04:59
|| Highest point is shown in green colour. 

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|| 05:03
|| Drag and place the probe on the highest point of the trajectory. 

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|| 05:07
||Note the '''Time, Range''' and '''Height''' at the highest point. 

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|| 05:12
|| Let us make tabular column for '''Cannon's Angle, Time Range''' and ''' Height'''. 

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|| 05:19
||I will enter the values for 10 degrees angle. 

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|| 05:27
|| Drag the probe back to its place. 

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|| 05:30
|| Similarly, I will change the cannon's angle to 20 degrees. 

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|| 05:35
||Launch the projectile and observe the trajectory. 

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|| 05:40
|| Place the probe on highest point of the trajectory. 

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|| 05:44
||Note the values of '''Time, Range''' and '''Height ''' in the table. 
I have entered the values in the table. 

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|| 05:55
|| As an assignment: 
change the values of cannon's angle and complete the tabular column. 

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|| 06:04
|| Click on '''Reset''' button to reset the simulation. 

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|| 06:08
|| Launch the projectile and observe the trajectory. 

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|| 06:13
|| Adjust the target on the base line so that projectile falls on the target. 

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||06:19
|| Launch the projectile and observe the trajectory. 

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|| 06:23
||Observe the stars as the projectile hits the target. 

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|| 06:27
|| By default,  '''slider''' is at 15 meter per second '''Initial speed'''. 

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|| 06:33
||'''Initial Speed''' can be changed between 0 to 30 meter per second. 

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|| 06:39
|| Drag the '''Initial Speed''' slider to 20 meter per second and launch the projectile. 

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|| 06:49
||Notice that projectile moves faster and falls at a greater distance on the base line. 

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|| 06:56
||Click on '''Slow''' radio-button and launch the projectile. 

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|| 07:01
||Observe that the projectile moves slowly. 

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|| 07:05
|| Notice that '''Slow''' radio button slows down the '''animation''' speed. 

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|| 07:10
||It does not reduce the projectile's speed. 

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|| 07:14
|| Click on yellow '''eraser''' icon to erase the earlier trajectories. 

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|| 07:20
|| Adjust the cannon's angle to minus 10 degrees and initial speed to 25 meter per second. 

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|| 07:28
||Launch the projectile. 

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|| 07:34
||Observe the trajectory and distance covered. 

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|| 07:38
|| Click on '''Velocity Vector's Total''' and '''Components''' check boxes. 

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|| 07:45
||Launch the projectile. 
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|| 07:48
|| Observe the '''Velocity vector''' and its components on the trajectory. 

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|| 07:54
||Un-check the boxes. 

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|| 07:57
 || Click on '''Acceleration Vectors' ''' '''Total''' and '''Components''' check boxes. 

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|| 08:03
||Launch the projectile and observe the trajectory. 

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||08:11
|| As an assignment, Observe the projectile motion by- 

1. Selecting various projectiles 

2. Changing initial speed and height of the pedestal. 

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|| 08:23
|| Next we will move on to ''' Vectors''' screen. 

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|| 08:27
||Click on '''Vectors''' screen. 

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|| 08:30
|| In this screen, we will explore how velocity, acceleration and force are affected by air resistance. 

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|| 08:39
|| '''Vectors''' screen has nearly same tools as in '''Intro''' screen. 

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|| 08:44
|| In this screen, pedestal's height is 0 metres and cannon's angle is 80 degrees. 

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|| 08:52
|| Change cannon's angle to 70 degrees and launch the projectile. 

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|| 09:03
|| Here, we have only one projectile - '''Cannonball'''. 

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|| 09:07
||We can change the diameter and mass by dragging. 

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|| 09:14
|| Uncheck '''Air Resistance''' check-box and launch the projectile. 

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|| 09:27
||Without air resistance, projectile moves to a greater altitude and longer distance .

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|| 09:34
|| Now click on the following check boxes- '''Velocity Vectors''', 

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|| 09:40
||'''Acceleration Vectors''', 

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|| 09:42
||'''Force Vectors'''.

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|| 09:44
||Launch the projectile. 

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|| 09:46
||You will see the vector components on the trajectory. 

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|| 09:51
|| Next we will move on to''' Drag''' screen. 

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|| 09:54
|| Click on '''Drag''' screen at the bottom of the interface. 

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|| 09:59
||In this screen, we will- determine the factors that affect the drag force, 

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|| 10:05
||observe the relation between drag force and velocity. 

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|| 10:10
|| Additionally, this screen has '''Drag Coefficient''' and '''Altitude '''sliders. 

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|| 10:16
|| Let us move the '''Drag Coefficient''' slider to '''0.04'''. 

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|| 10:21
||Notice the shape of the projectile. It appears as a water drop. 

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|| 10:27
|| Launch the projectile and observe the trajectory. 

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|| 10:37
||When the drag coefficient is small, projectile travels to a greater altitude and greater distance. 

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|| 10:45
|| Drag and place the '''probe''' on the highest point. 

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|| 10:49
||Probe displays the '''Time, Range''' and '''height''' of the projectile. 

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|| 10:54
||Drag the probe back to its place. 

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|| 10:57
|| Change '''Initial speed''' to '''14 meter''' per second and '''Drag Coefficient''' to '''0.45'''. 

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|| 11:06
||Click '''Zoom In''' button to zoom the view. 

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|| 11:11
||Launch the projectile and observe the trajectory. 

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|| 11:17
|| Click on '''Zoom Out ''' button to show normal view. 

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|| 11:21
|| Now move the '''Drag coefficient '''slider to '''0.50'''. 

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|| 11:27
||Change the initial speed to '''24 meter per second'''. 

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|| 11:32
||Drag the '''Altitude''' slider to '''1700''' meter and launch the projectile. 

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|| 11:45
||Observe the trajectory. 

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|| 11:50
|| Using measuring tape, measure the distance covered by the projectile. 

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|| 12:06
|| Now we will move on to '''Lab''' screen. 

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|| 12:09
|| Click on '''Lab''' screen. 

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|| 12:12
||In this screen, we have a list of projectiles. 

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|| 12:16
|| Let us select the projectile as '''Custom'''. 

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|| 12:20
||Here we can change  values of  '''Mass''', 

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|| 12:24
||'''Diameter''',

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|| 12:26
||'''Gravity''', 

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|| 12:28
||'''Altitude''' and '''Drag Coefficient''' manually. 

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||  12:33
|| Beside each attribute, notice an yellow coloured '''edit''' button. 

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|| 12:38
||These buttons are used to change the values manually. 

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|| 12:43
|| Now I will change '''Gravity''' value. 

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|| 12:46
||Click on '''edit''' button corresponding to '''Gravity'''. 

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|| 12:50
||A key pad opens. 

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|| 12:53
||Select '''15''' and click '''Enter'''. 

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|| 12:59
|| Check  '''Air Resistance ''' check box. 

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|| 13:03
||Change the '''Altitude''' value to '''2000 meter''' using  edit button. 

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|| 13:11
||Launch the projectile and observe the trajectory. 

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||13:17
|| Drag and place the probe to measure the highest point. 

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|| 13:22
|| As an assignment, change various custom parameter and launch the projectile.  

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|| 13:29
|| Let us summarize. 

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|| 13:31
|| In this tutorial, we have demonstrated '''Projectile Motion PhET simulation''' . 

|- 
|| 13:37
|| Using this simulation, we have: 

1. Determined how each parameter affects the trajectory of an object 

|- 
|| 13:45
||2. Estimated where an object will land, given its initial conditions. 

|- 
|| 13:51
||3. Determined how horizontal and vertical motion of a projectile are independent. 

|-
||13:58
||4. Investigated the variables that affect the drag force. 

|- 
|| 14:03
||5. Examined the effect of drag force on the velocity and acceleration. 

|- 
|| 14:09
|| The video at the following link summarizes the '''Spoken Tutorial''' project. 
Please download and watch it. 

|- 
|| 14:16
|| The Spoken Tutorial Project team conducts workshops using spoken tutorials and gives certificates on passing online tests. 

|- 
|| 14:26
||For more details, please write to us.  Please post your timed queries on this forum. 

|- 
|| 14:33
|| This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching. 

|- 
|| 14:41
|| Spoken Tutorial Project is funded by '''NMEICT, MHRD,''' Government of India. 
More information on this mission is available at this link. 

|- 
|| 14:52
|| This is Madhuri Ganapathi from IIT Bombay, singing off. 

Thank you for joining. 
|-

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