Tuesday, 22 January 2013

Motion of an Object II (Assignment)

1. Download the following video from Dropbox using your iPad (procedure to do that can be found here)

  • Dropbox app -> "Y3 LTL Class" -> "Classroom activities" -> "02 Kinematics" -> "20130125 Motion of an object II"
  • Download "table tennis ball.mp4"
2. Complete the following questions:

  • Determine the ball's positions, distance from the starting point of the motion, clock reading and time interval from the start of the video. Record it in a table with the following column headings. (The centre of the ball begins its motion at the position of 2.7 cm when the clock reading is 0 s, each white line represent 10 cm interval on the metre rule)
  • Describe the motion of the ball qualitatively (i.e., with words)
  • Compare with the assignment you have just completed (refer to here), state the difference(s) between the motion of the table tennis ball and the toy cars.
  • Create a possible motion map of the table tennis ball.
  • Use Graphical Analysis app to determine the linearised relation between the distance from starting point (y-axis) and time interval (x-axis).

3. Find a way to put all your work above in a single document (I would suggest Evernote or some handwriting app that you can insert pictures). This is in anticipation of future larger projects and experiment.

Hint to complete the assignment using CoachMyVideo app
Do you need to capture the positions of the ball at equal position intervals?


Creating Motion Maps (Assignment)

  1. Download "02 Motion Map.pdf" (from dropbox -> "Y3 LTL Class" -> "Classroom activities" -> "02 Kinematics"-> "20130122 Motion Maps").
  2. Create the motion maps for the four position vs clock reading graphs 
  3. Use any drawing app (showme app, handwriting app, etc) to create these maps for presentation on the next lesson on 25/01/2013.

Monday, 21 January 2013

Motion of an object (Assignment)

How do you describe a moving object?

Data collection

1. Download the following video from Dropbox using your iPad
  • Dropbox app -> "Y3 LTL Class" -> "Classroom activities" -> "02 Kinematics".
  • Access "Video1.mp4", click the star icon on the top right hand corner to start the download.
  • Once downloaded, click on the "download icon" at the extreme top right hand to "Save to Photo Library".
2. Open the video using CoachMyVideo app to view downloaded video, capture the object's positions and clock readings (the reading on the top left hand).

3. Use Graphical Analysis app to determine the relation between the 2 quantities.

4. Repeat step 1 to 3 for "Video02.mp4" for the 2 moving objects.

5. Take photos of your data collection and screenshots of the graph produced and email to me.


After completing the data collection and analysis, please complete these questions.

Monday, 14 January 2013

Length Measurements

Reading Assignment

  • Download the notes on "20130114 Y3 Measurement notes 2.pdf" from the shared dropbox folder (refer to your email).

Vernier Callipers

  • Read the section on "Vernier Callipers"
  • Download this iPhone app (http://itun.es/sg/FVJBH.i). Refer to pictures below regarding the setting and how to use the app. Use the app to gain an understanding on how to use the Vernier Callipers.

  • Complete Example 10 and 11.

Micrometer Screw Gauge

  • Read the section "Micrometer Screw Gauge".
  • Watch the following video on how to read micrometer screw gauge

  • Complete example 6 - 9.

Tuesday, 8 January 2013

Motion of a falling object (Measurement practical)


An object (eg. a rubber ball) is dropped from the 4th floor.

  • Predict the motion of the ball.


As a group, design a experiment to investigate the motion of a ball dropped from the 4th floor. Appoint a group leader and a scribe/photographer for the activity.In your account youshould pay particular attention to

  • the variables you will consider for falling objects,
  • the apparatus you use,
  • the procedure to be followed,
  • any safetyprecautions you would take,

Represent the data collected in a manner that helps you to justify your predication of the motion of a falling object.

Identify the possible error(s) in your experiment.

(Hint: You will probably need to

  • refer to the height measurement task that you did on Monday 7/1/13
  • use Movie app/CoachMVideo app to capture the fall
  • use CoachMVideo app for frame-by-frame and for position/timing)


  • Email completed softcopy writeup before 1159 pm on 13/1/13. We need the data for the lesson on Mon 14/1/13.
  • Complete the questions found here before 14/1/13.


Some suggested apps or tools for writeup:

  • Evernote - type, sketch (with skitch), insert photos, etc
  • Note - type only
  • Pic Collage - difficult to type but very good for visual representation using photos
  • Google Docs - easier to use on laptop/desktop, easy to collaborate on the same document

Using CoachMVideo App


Using google drive to manipulate data

You need a Google account, download iOS google drive and log in.

Create "New Spreadsheet"
Use formulae to compute the new cell value


Friday, 4 January 2013

Assignment - Powers of Ten

Please complete before the next lesson.
  • Physics Matters - 1.2 Physical Quantities and SI Units (Pg 3 - 5)
  • Video assignment. Click here to access the assignment. 
"Physics is the study of how nature work from the smallest, like the atoms, to the largest, like the galaxies. The range of measured quantities in the universe is there fore enormous.
This video will demonstrate the scale of things that physicists, and you, are dealing with everyday."

Tuesday, 1 January 2013

Measure height with ...

The following concerns a question in a physics degree exam at the University of Copenhagen:

"Describe how to determine the height of a skyscraper with a barometer."

One student replied:

"You tie a long piece of string to the neck of the barometer, then lower the barometer from the roof of the skyscraper to the ground. The length of the string plus the length of the barometer will equal the height of the building."

This highly original answer so incensed the examiner that the student was failed immediately. The student appealed on the grounds that his answer was indisputably correct, and the university appointed an independent arbiter to decide the case.

The arbiter judged that the answer was indeed correct, but did not display any noticeable knowledge of physics. To resolve the problem it was decided to call the student in and allow him six minutes in which to provide a verbal answer that showed at least a minimal familiarity with the basic principles of physics.

For five minutes the student sat in silence, forehead creased in thought. The arbiter reminded him that time was running out, to which the student replied that he had several extremely relevant answers, but couldn't make up his mind which to use. On being advised to hurry up the student replied as follows:

"Firstly, you could take the barometer up to the roof of the skyscraper, drop it over the edge, and measure the time it takes to reach the ground. The height of the building can then be worked out from the formula H = 0.5 * g * t squared. But bad luck on the barometer."

"Or if the sun is shining you could measure the height of the barometer, then set it on end and measure the length of its shadow. Then you measure the length of the skyscraper's shadow, and thereafter it is a simple matter of proportional arithmetic to work out the height of the skyscraper."

"But if you wanted to be highly scientific about it, you could tie a short piece of string to the barometer and swing it like a pendulum, first at ground level and then on the roof of the skyscraper. The height is worked out by the difference in the gravitational restoring force T =2 pi sqr root (l /g)."

"Or if the skyscraper has an outside emergency staircase, it would be easier to walk up it and mark off the height of the skyscraper in barometer lengths, then add them up."

"If you merely wanted to be boring and orthodox about it, of course, you could use the barometer to measure the air pressure on the roof of the skyscraper and on the ground, and convert the difference in millibars into feet to give the height of the building."

"But since we are constantly being exhorted to exercise independence of mind and apply scientific methods, undoubtedly the best way would be to knock on the janitor's door and say to him 'If you would like a nice new barometer, I will give you this one if you tell me the height of this skyscraper'."

The student was Niels Bohr, the only Dane to win the Nobel Prize for physics.

Extracted from: http://www.snopes.com/college/exam/barometer.asp


Luckily for you, for this task you will not be given a barometer. You are given a rope/string of 20 metres. You need to design a method to determine the height of the building without using any length measurement equipment (Fig.1). During the measurement, you are not to be anywhere beyond the boundary shown in Fig.2.



You are to document your entire process via writings, photos, etc using Evernote or equivalent app(s). Evaluate your design as thoroughly as possible.


Short 2 to 3 mins presentation (about 2 slides) of how the measurement is done, your results and evaluation of your results and design.


Send/share your process documentation and product(s) with me at tatlee08@gmail.com.