Kinematics

Position & Displacement Page

Mary is at the park.  She is willing to help demonstrate/explain the concepts of position and displacement.  Possible questions to explore include:

How do we describe Mary's position? ...in words? ...in symbols?  What do we use for a reference point?  What if we change the reference point?  What if Mary moves?  What is Mary's displacement when she moves?  How do we calculate that?  What is the difference between the distance Mary travels and her displacement?

Controls:

The "Walk" and "Stop" buttons control Mary's movement.  The "Reset" button returns everything to its original position.  A keyboard can also be used: left/right arrows to move, down arrow to stop, spacebar to reset.  The red marker can be dragged with a mouse/finger, or moved with the "a" and"s" keys on the keyboard as desired, e.g. to mark a reference point, or Mary's starting position, etc.

Each rectangle on the scale across the bottom of the picture represents a distance of 1 metre.

The bounded region in the lower part of the screen is a simple sketchpad.  Using a stylus, finger, or mouse, you can write in this region.  Possible uses include demonstrating proper notation, marking Mary's movements, etc.  The buttons at the top right of the sketchpad switch between pen and eraser, and allow for clearing of the sketchpad.

Mary likes walking.  If she walks off the screen she will keep going unless you bring her back or reset the animation.

Speed vs. Velocity Page

This page shows three animated vehicles moving with different velocities.  Possible uses for this page include illustrating how speed is measured, and highlighting the difference between speed and velocity.  Possible questions include "What is the vehicle's speed?", "What is the vehicle's velocity?", "How do we describe the velocity in words, in symbols?"

Controls:

Use the "Run/Pause/Resume" and "Reset" buttons to control the vehicle's motion.  Use the number buttons to select a vehicle.  A keyboard can also be used: use the down arrow to start/pause/resume the motion, the spacebar to reset, and number keys to select a vehicle.

Marks on the road are 1 metre apart, with every 5 m highlighted in yellow.

The bounded region in the lower part of the screen is a simple sketchpad which can be used for marking motions, demonstrating notation, and so on.  Pen/eraser/clear buttons are at the top right of the sketchpad.

Changing Velocity Page

This page shows three animated vehicles.  Vehicle 1 is speeding up, 2 is slowing, and 3 has a constant velocity.  Possible uses for this page include differentiating between average and instantaneous speeds, and showing how the instantaneous speed at a point can be approximated by measuring average speed over a short distance.  Possible questions include "Is the car changing speed?", "How can we tell?", and "How do we determine the instantaneous speed of an object at a point?".

Marks on the road are 1 metre apart, with every 5 m highlighted in yellow.

When the "Measure" button is toggled on, the green and red markers can be repositioned, and the clock reading when the car reaches each marker will be displayed.  This allows the average speed between those two points to be calculated.

Controls:

Use the "Run/Pause/Resume" and "Reset" buttons to control the vehicle's motion.  Use the number buttons to select a scenario.  The "Measure" button toggles the ability to move the markers and take measurements on/off.  When "on", the green and red arrow buttons move their respective markers 1 metre at a time.

A keyboard can also be used:

• down arrow to start/pause/resume the motion.
• spacebar to reset.
• number keys to select a vehicle.
• "m" key to toggle measurement on/off.
• When measurement is on, "a" and "s" to move green marker left/right, and "d" and "f" to move the right marker.

As with previous pages, the lower part of the screen is a simple sketchpad to be used as desired.