02 Kinematics

Sky-Diving and Terminal Velocity


This is a wonderful applet created by Abdul Latiff, another Physics teacher from Singapore, on how air resistance varies during a sky-dive with a parachute. It clearly demonstrates how two different values of terminal velocity can be achieved during the dive.

Incidentally, there is a video on Youtube that complements the applet very well. I have changed the default values of the terminal velocities to match those of the video below for consistency.

Also relevant is the following javascript simulation that I made in 2016 which can show the changes in displacement, velocity and acceleration throughout the drop.

Equation of Motion App

Access the app in full screen here: https://www.geogebra.org/m/mfvvhjrj

This app is designed to give students practice in interpreting velocity-time graphs with various scenarios, such as more complex examples involving negative velocity and acceleration. Answers will be given if student is wrong.

Use this to embed into SLS or another LMS.

<iframe scrolling="no" title="Equations of Motion" src="https://www.geogebra.org/material/iframe/id/mfvvhjrj/width/700/height/480/border/888888/sfsb/true/smb/false/stb/false/stbh/false/ai/false/asb/false/sri/false/rc/false/ld/false/sdz/false/ctl/false" width="700px" height="480px" style="border:0px;"> </iframe>

Bouncing Ball Animation using Python

For a fullscreen view, visit https://www.glowscript.org/#/user/wboson2007/folder/MyPrograms/program/Bouncing

Modified this python simulation from Dr Darren Tan’s work at https://sciencesamurai.trinket.io/a-level-physics-programming#/collisions/bouncing-ball

Wanted to try out a different way of creating simulations. Added the acceleration-time graph in place of his energy-time graph, in preparation for the teaching of kinematics. Also assuming no energy loss during collisions for simplicity.

For Singapore teachers, I have submitted a request to SLS for this URL to be whitelisted for embedding. Once approved, glowscript simulations can be embedded as part of the lesson. For the time being, a URL link out to the simulation will have to do.

Multiple Representation of Vertical Throw

One common misconception among new learners of kinematics is that acceleration of an object being thrown upward is zero at the top of the path when it is momentarily at rest. I created this interactive, along with the 3 graphs in order to help students relate the vectors to the graphical representation of motion.

It is also worth noting that students often have conflicting ideas of the acceleration at the beginning of the throw, as they are aware that a resultant upward acceleration is necessary for the object to start moving upward in the first place. Hence, it must be stressed that the animation begins after the ball has left the throwing hand.

For a view that is optimized for your screen, visit https://www.geogebra.org/m/zvsydy9f.