RFE 2001.06.09.001

In all three modes (linear, circular, parabolic), add some units in the top left corner. Also add units on the axes.

url: Angular Velocity/Basic Facts/Simulate It

In all three modes, in the top left corner, write

Angular velocity (w): ... (This should be the Greek letter omega, not the Latin letter double-u.)

Radius (r): ...

Areal velocity (dA/dt) = 1/2 r^2w = ... (Write a proper superscript '2' above the 'r'.)

On the vertical axis, add '(rad/s)' after 'Areal Velocity' and on the horizontal axis add '(s)' after 'Time'.

(2001.06.09) Hans Laue

Completed
2001.06.19 - Jeremiah Van Oosten

RFE 2001.09.18.001 STATUS: OPEN

In the Energy Race, there is nothing to indicate which object has gone down the incline after the objects have disappeared at the bottom of the window.

Also, the Start button has to be hit twice after Reset. Once should be enough.

url: Energy/Energy Conservation/Simulate It/Energy Race

Details:

When an object is placed on the incline, in the empty white space to the right of the incline, print the name of the object, e.g., "Brick" or "Hoop". Keep this name displayed until somebody hits Reset.

2001.09.18 Hans Laue

BUG 2001.07.24.001 STATUS: FINISHED

There are three small changes here as detailed below.

url: Force/Normal/Explain It

1. The '2.00Kg' label on the block sitting on the springs should be changed to '2.00 kg', i.e., a lower case 'k' and a space between the numerical value and the unit.
2. The color of the weight vector should be changed from blue to green, to conform to our regular color scheme.
3. It would be good if there were more variation in spring length from most compressed to least compressed, so that it is more eye-catching that the length of the springs is variable. Can this be done easily? At least to double the range through which the length of the springs is varied?

(2001.07.24) Hans Laue

Completed (2001.07.24) Jeremiah Van Oosten

BUG 2001.08.26.001 STATUS: FINISHED

Change the label on the Acceleration slider so that the unit is fully displayed.

url: Force/Normal Force/Explain It

Details:
At present, the "^2" part of the acceleration unit on the acceleration slider is not displayed. Reorganize this as follows. Instead of "Accel. : 0.0 m/s^2" label the Acceleration slider as follows: "Acc(m/s^2): 0.0" and the Velocity slider accordingly: "Vel(m/s): 0.0". If you can write a superscript "2" instead of "^2", that would be much better, of course. (The Simulate It item has a real superscript.)
2001.08.26 Hans Laue

Completed Jeremiah Van Oosten (08.28.2001)

RFE 2001.08.30.001 STATUS: FINISHED

Show different fbd's in the Lab Frame and Object Frame modes and display the acceleration vector differently in the two frames. (Hans will modify the info page accordingly.)

url: Force/Normal Force/Explain It

Details:
In the Lab Frame mode, place the tail end of the acceleration vector on the table top near the right edge of the table. When the table gets dragged up and down, this tail end will have to be dragged along. Also, when the tip of the acceleration vector gets dragged (or the acceleration slider is used), the table top is moving on the screen and the tail end of the acceleration vector will have to move with it. During the animation, the acceleration vector will move rigidly with the table top to suggest that the acceleration vector is a property of the table.

In the Object Frame mode, place the acceleration vector exactly where it is now, but change its label from a lower case a to an upper case A. In this frame, the acceleration shown will represent the acceleration of the Object Frame relative to the Lab frame, not the acceleration of the table. The latter is zero in this frame.

Also, in the Object Frame mode, add a third vector to the fbd. The third vector is drawn in black and labeled F_fict = ... N. The dots will be replaced by the value of the magnitude of this fictitious force. This value is equal to ma, where m = 2 and a is equal to the magnitude of the acceleration (between 0 and 4). The direction of the black arrow is always opposite to that of the acceleration. Thus, when the acceleration is up, the fictitious force will side-by-side with the weight in the fbd, and when the acceleration is down, the fictitious force will be side-by-side with the normal force in the fbd. To not show the force vectors on top of each other, show force vectors that point in the same direction slightly offset from each other horizontally. I suggest to have the tail ends of two such vectors roughly at the left and right edges of the black dot representing the object in the fbd. Also put the label of the new fictitious force arrow below and to the right of the tip when the arrow is up and above and to the right of the tip when the arrow is down. That way it won't overlap with the label of the other force.

2001.08.30 Hans Laue

BUG 2001.08.30.001 STATUS: OPEN

On p.5 of the Explain It session, an old version of the applet is shown instead of the new one.

url: Force/Normal Force/Explain It

Details:
On page 5, the applet starts with some special initial values. Presently, the old version of the applet is used. Replace this with the new version, using the same settings as on the present page 5.

2001.08.30 Hans Laue

RFE 2001.08.30.002 STATUS: OPEN

Please make some additions and changes to the Accelerating Incline applet produced by the Edmonton group.

url: Accelerating Incline

Details:

1. In addition to the three force vectors (normal, weight, friction), allow for display of the three acceleration vectors:
   • the acceleration a of the block relative to the lab
   • the acceleration a' of the block relative to the incline
   • the acceleration A of the incline relative to the lab

   The three acceleration vectors must add vectorially so that a = a' + A. A is determined by one of the sliders, the other two accelerations must be present in the code somehow and are calculated from things like the angle of the incline and the other variables affecting the motion.

   Actually, we should display not the accelerations themselves but the mass of the block times these accelerations. (At present the mass of the block is set to 1 kg, so the product ma is numerically equal to just a. Thus, all we have to do is display the acceleration vectors but label them 'ma' instead of a, etc. The reason for being interested in ma rather than a is that ma is equal to the net force, so that by dragging ma into the force diagram one can demonstrate that Newton's second law is obeyed.

   Which ones of the three accelerations are going to be displayed at any given time, and which ones of the three force vectors, will be determined by a pull-down selection tool that is going to replace the present pull-down menu accessible in the lower right-hand corner. This selection tool will also allow any vectors that have been checked to be moved together as a block. The present "FBD" check box will become redundant as a result.

   In its default state, the vector A is drawn inside the incline (or near it if the angle is very small) and the other two acceleration vectors are drawn with their tail ends at the center of the block. When the system is moving, these acceleration vectors move along with the incline and the block.

   We need to decide on three different colors for the three accelerations. a should be the standard orange for acceleration, but the two other accelerations should be slightly different. There are also the colors of the components to decide on. See below.

2. The display/hide/move of force vectors will be handled together with the display/hide/move of acceleration vectors with a Photoshop-like selection device that can be accessed via the icon in the lower right-hand corner.
3. The present 'Fix FBD' check box and its functionality should be extended to a 'Fix Vectors' check box that will fix all vectors, forces and accelerations, onto the incline and block. That means that when this check box is selected, the pull-down menu should not allow the force vectors to be moved, but should continue to allow individual force vectors to be hidden or displayed. Thus, this menu has to stay accessible when this box is checked, which is not the case at present. When the box gets checked, vectors that are scattered all over the window have to be placed in their standard positions on the incline and block.
4. The FBD Components check box should be replaced by a more general Components check box. When that is checked, the Photoshop pull-down menu has a different functionality: it looks the same as when the Components check box is unchecked, but the items checked in the pull-down menu now affect the components of the vectors. Thus, if an acceleration vector is checked to be displayed, then its components will now be displayed. This will be in addition to whatever vectors are already on the screen. The components will be shown with their tail ends at the tail end of the vector. Then, when the Component check box gets unchecked, the pull-down menu will affect the vectors and leave undisturbed whatever components may be on the screen.

   There have to be two kinds of components displayable, components relative to x,y axes that are horizontal and vertical and componnents relative to x',y' axes that are down the incline and perpendicular to the incline, respectively. That choice can perhaps be set by means of a button on the Photoshop pull-down menu. There also has to be a facility to only affect either the x or the y components, i.e., one must be able to move or hide the x-component without affecting the y-component. Again, maybe this choice could be in the same pull-down menu.

5. The FBD check box should be replaced with a check box labeled 'Vectors' that toggles with the 'Components' check box: only one of them can be selected at a time. When the Vectors check box is selected the Components check box gets unselected automatically and the pull-down menu lets you work on the vectors. Similarly, when the Components check box gets selected. The other three check boxes will be the Fix Vectors and the present Ramp and Block.
6. The layout of the control panels should be changed. At the top there is only the logo bar, the action window is in the middle, and at the bottom are all the controls. Can the angle, acceleration and mu values not be displayed with the sliders, thus saving some vertical space and having a more direct display of these values? If the row of check boxes is placed directly above the final row of buttons, then Ramp and Block should come first in this row, and the Vectors and Components check boxes last, so that they are placed next to the button for the pull-down menu.
7. There will have to be some other adjustments so that the weight vector is visible in its entirety under all conditions.

2001.08.30 Hans Laue

RFE 2001.06.09.001

In both the sine and trigonometric applets, the vertical dotted line in the unit circle is covered by the solid red color when the line is inside the angle

url: Function/Trigonometric/Simulate It/Sine Function
url: Function/Trigonometric/Simulate It/Trig Functions

In both the sine and trigonometric applets, the vertical dotted line in the unit circle is covered by the solid red color when the line is inside the angle. The same is not true for the horizontal dotted line showing the cosine.

This is not a problem when one goes around the circle a few times and the solid color has changed to something other than red. At some point there will then be a problem with the blue cosine line being masked by the blue background of the angle.

I suggest the following resolution. In the range from -10 pi to 10 pi, show the vertical stippled line representing the sine in black WHEN it falls inside the solid color of the angle. Show it in red, even if the angle is in this range when the vertical line is on a white background. Use a black dotted line both in the circle on the left and in the graph on the right. Outside of this angular range, show the vertical line always as red because there it is clearly visible against the background. Repeat this procedure when the angle gets so large that it again is in the red color range.

I have simply colored the inside of the unit circle with white all the time.  That way both lines are visible all the time.  Is this acceptable?
(2001.06.20) Jeremiah

For the cosine, let's not worry about this because for angles near 0, the blue stippled line is clearly visible and by the time students get to the blue angles they will know what is going on.
(2001.06.09) Hans Laue

Completed.
(2001.06.20) Jeremiah Van Oosten

RFE 2001.06.09.002

Interchange the order of the button sets labeled 'Functions' and 'Vertical Lines' and rename both sets to 'Graphs' and 'Projections', respectively.

url: Function/Trigonometric/Simulate It/Sine Function
url: Function/Trigonometric/Simulate It/Trig Functions
Put the button set labeled 'Vertical Lines' on the left (where 'Functions' is now) and put 'Functions' on the right (where Vertical Lines is now). Relabel the two button sets as indicated above. Reasons are as follows.

'Projections' belongs with the circle on the left and 'Graphs' with the graphs on the right. So the button sets will be more intuitive to use this way. The new names reflect better the nature of what is being displayed. (The lines are not always vertical, for example. The cosine line is horizontal in the circle, so we should not refer to it as vertical.)

(2001.06.09) Hans Laue

Completed.

(2001.06.20) Jeremiah Van Oosten

BUG 2001.08.11.001 STATUS: OPEN

The name of the applet cannot be changed in applet.html. Right now the name is set at 'Motion Applet'. I would like it to be 'Four Motions'.

url: Interaction/Basic Facts/Get A Glimpse

url: Acceleration/Av. and Inst./Explain It, p.3

The applet is also being used under Acceleration (see url above). Inside the folder accel/av_inst/explain/fourmotions, there is the file applet.html. This file contains a PARAM tag that requests the applet name to be 'Four Motions'. The tag is being ignored.
2001.08.11 Hans Laue

BUG 2001.08.11.002 STATUS: OPEN

There is no info shown on the info menu, even though an info.html file exists and seems to be linked properly in the applet.html file with the tag .

url: Interaction/Get A Glimpse

I have put an info.html file at classes/info/interaction/fourmotions, but the applet is not finding it.

I have also inserted the tag into applet.html, which did not do the trick. This applet.html is at content/interaction/glimpse/.

2001.08.11 and 2001.09.04 Hans Laue

BUG 2001.08.10.001 STATUS: FIXED

The Slingshot Effect applet (planet3) does not connect to the info.html page. It points to the old Help folder. This may have to be changed in the source code because page2.html (which replaces applet.html in this case) does not refer to the help folder.

url: Reference Frames/Inertial/Galilean Relat'y/Simulate It/Slingshot Effect

The new INFO_URL parameter tag is present in page2.html, and also a tag that specifies the name of the applet as "Slingshot Effect". Neither one of these tags is effective at present.
2001.08.10 Hans Laue

BUG 2001.08.10.002 STATUS: OPEN

Change 'sun's velocity' to 'planet's velocity' on the slider in the lower left corner of the control panel and change 'v=' in the fourth and last item of the data table at the top left to 'velocity (v):' where the 'v' should have an arrow above it and be in bold.

url: Reference Frames/Inertial/Galilean Relat'y/Simulate It/Slingshot Effect

2001.08.10 Hans Laue

BUG 2001.08.13.001 STATUS: OPEN, but PARTLY FIXED

The slider titled "sun's velocity", which is to become "planet's velocity" shows the wrong velocity velocity values. FIXED.

There are also a few small editorial things that need to be taken care of.

url: Reference Frames/Inertial/Galilean Relat'y/Simulate It/Slingshot Effect

Details:
The slider titled "sun's velocity", which is to become "planet's velocity" shows the wrong velocity velocity values. Instead of 1 km/s it show something close to 1.96 km/s. In other words, the slider is using an incorrect scale factor. The velocity vectors add correctly and, if the scale change is made on the slider the printed velociy values aer correct as well. FIXED.

The editorial things that need to be taken care of are:

• Change the fourth one of the printed values from "v =" to "velocity (v):", where "v" should be in boldface with an arrow on top. Write unit as "km/s" instead of "km". FIXED.
• For the check box labels "probe rel' stars" add "(v)" behind "stars" and for "probe rel' planet" add "(v')" behind "planet". Both "v" and "v'" are vector symbols and should be displayed as in the previous bullet. Make room for the extra symbols by reducing the slider's width. OPEN.
• The RESET button should have a different action from the REPLAY button. It should set the velocity slider to zero and should unselect all buttons, like the trace and velocity buttons. It does not do these things right now, only resets the probe to its initial position, which is what the REPLAY button does. OPEN.

2001.08.13 Hans Laue








• --> RFE 2001.09.18.001 STATUS: OPEN

  In Planet 1 and Planet 2, make the cursor change appearance when it is moved over the graph area, assuming the graph is being displayed.

  url: Reference Frames/Inertial Frames/Galilean Relativity/Gal'n Kinematics/Simulate It/Planet Motion 1

  url: Reference Frames/Inertial Frames/Galilean Relativity/Gal'n Kinematics/Simulate It/Planet Motion 1

  Details:

  The user needs to be alerted to the fact that the applet provides a special functionality when the cursor is over the area of the graph. Change the cursor to a pointing hand, as we have now in the vector applets when a vector can be dragged.

  Do the same in the angular velocity applet.

  The same cursor symbol can also be used when the control key is held down while the graph is being dragged.

  2001.09.18 Hans Laue
• BUG 2001.09.18 STATUS: OPEN

  Three small changes in the data area of the Cycloid applet.

  url: Reference Frames/Inertial Frames/Galilean Rel'y/Gal'n Kinematics/Rolling Motion

  Details:

  1. Change the icon on the data button to the new icon.
  2. In the right column of data, change "Cycloid (x)" and "Cyclid (y)" to "Rolling Point (x)" and "Rolling Point (y)".
  3. In the right column of data, eliminate the last entry "Center (y)". Replace "Center (x)" by "Center of spool (x)".

  2001.09.18 Hans Laue

RFE/BUG 2001.09.12.001 STATUS: OPEN

Update the INFO page for the Rolling Motion applet (formerly called 'Cycloid'). Also, link the Info page to the MAP logo pull-down menu. Picture the spool when it is in a different phase. Add a toggle button that either will display or hide the numerical data. In the default state, the data will be hidden. The values for the coordinates of the center of the spool are incorrect. It looks as if the values shown are in pixels. They should be in meters.

url: Reference Frame/Inertial/Galilean/Simulate It/Rolling Motion

Details:
The applet has been updated so that there is no longer a button with a question mark providing HELP, but the present info page still lists this button as Item 6. The present Item 6 should be deleted from the Info page and the numbers of the following items should all be moved to fill the gap.

I have already edited the text of the Info page. In particular, I have deleted the item in the list that referred to Help. So, please start where I left off.

Also, I would suggest you do not give your email address here. It can become outdated (the present address already is?).

Try to use a picture of the applet in which the velocity vectors are somewhat larger and there is minimal overlap of labels and vectors.

The Info page is not connected to the pull-down menu at present.

2001.09.12 Hans Laue

BUG 2001.09.12.001 STATUS: OPEN

The labels on the sliders of the Rolling Motion applet (formerly 'Cycloid') need to be fully displayed including all values and units. Make a few changes to the labeling of items in the drop-down menu.

url: Reference Frame/Inertial/Galilean/Simulate It/Rolling Motion

Details:
For the slider labels, replace 'Angular Velocity:' by 'Ang. Vel. (rad/s):', 'Radius of Cycloid:' by 'Rad. of Cycloid (m):', and 'Inner Radius:' by 'Inner Rad. (m):'. That way, there should be enough room for all values and units. Also, please center the labels over the sliders. The same goes for the labels 'Orientation' and 'Velocity Vectors'.

On the drop-down menu, spell 'all' as 'All' and 'none' as 'None' to be consistent with the spelling of the other labels.

Make the following label changes in the drop-down menu:

'Cycloid point in lab frame' to 'Spool point in lab frame'
'Center of wheel in lab frame' to 'Center of spool in lab frame'
'Cycloid point in wheel's frame' to 'Spool point in spool's frame'

2001.09.12 Hans Laue

RFE 2001.09.12.002 STATUS: OPEN

Add a button to both Planet 1, Planet 2, and Planet 3 that will either display or hide the data currently displayed on the screen. In the default state, the data should be hidden.

Also, center all labels over the sliders and over any check boxes. In Planet 1 and Planet 2, add in brackets '(u)' to 'sun's velocity'.

The Info file picture and text needs to be updated. The present picture still has the question mark help button and has the old labeling of the three velocity vectors. Also, the control panel looks quite different now.

url: Angular Velocity/Planetary Motion//Simulate It/Planet 1

url: Angular Velocity/Planetary Motion/Simulate It/Planet 2

url: Reference Frame/Inertial/Galilean/Simulate It/Slingshot Effect

Details:

2001.09.12.002 Hans Laue

BUG 2001.09.14.001 STATUS: OPEN

There are four small changes needed to the Cycloid applet.

url: Reference Frames/Inertial Frames/Galilean Relat'y/Gal'n Kinematics/Simulate It/Rolling Motion

Details:

1. For the last button on the right, use a new icon suggesting data. (At present we have the vector components icon there.) Change the tool tip from 'Toggle Components' to 'Toggle Data'.
2. Make sure the slider labels stay centered after using the sliders.
3. On the first slider, replace 'Ang. Vel.' by 'Ang. Speed'.
4. On the drop-down menu, add
   • '(v)' after 'Spool point in lab frame'
   • '(u)' after 'Center of spool in lab frame'
   • '(v')' after 'Spool point in spool's frame'

2001.09.14 and 2001.09.15 Hans Laue

RFE 2001.09.20.001 STATUS: OPEN

To SHM applet, add also a display of the velocity and the acceleration. (So far we have only discussed the display of the position of the oscillator.) Do this only for the undamped oscillator, not for the damped oscillator.

url: does not exist, new applet presently under construction

Details:

Do something like what Andrew did with his Acceleration/Instantaneous/Simulate It applet, and create a bunch of check boxes that let you either display or hide certain features.

1. There are three elements to the display: the circular motion on the left, the up-and-down shm in the middle, and the graphical representation of the middle motion on the right. Create checkboxes for all three, so that any one, or two, or three can be viewed at one time.
2. Add a checkbox that lets you view the velocity, again in the three display modes. On the left, the velocity vector is tangential to the circle and points in the direction of motion. Its magnitude is equal to rw, where 'r' is the radius of the circle (amplitude of the shm) and 'w' (Greek letter omega) is the angular frequency. (This w is equal to w₀ in the damped motion.) Choose a suitable scale for the velocity vector so that for the range of w possible, the magnitude of rw is not going to exceed the size of the screen.

   Allow the user to view the velocity vector on the left in two different ways: attached to the revolving point and attached to the center of the circle. (Andrew has something like this for his acceleration: accel 1 and accel 2.) In the mode where the velocity vector has its tail end attached to the center of the circle, only in that view, allow the graphical display of the velocity. Reason: the vertical coordinate of the graph is the projection of the velocity vector that is attached at the center of the circle.

   However, in the middle view (shm) display the velocity in either view 1 or view 2. In one case there will be a vertical velocity vector attached to the oscillating block (this vector is a projection of the vector revolving with the point), in the other case there will be a vertical velocity vector attached to the equilibrium position of the shm.

3. Do something similar for acceleration as for velocity. When the velocity vector is attached to the origin, its tip traces out a circle on the left. Draw this circle in magenta. When the acceleration check box is ticked (accel 1) attach an acceleration vector to the tip of the revolving velocity vector. This acceleration vector points in the direction of motion of the tip and has a magnitude rw². Choose a reasonable scale for this vector. Also allow display of a second acceleration vector (upon checking a box) that has its tail end attached to the center of the circle. This acceleration vector points opposite to the position vector.

   Again, allow checking of projections of these two acceleration vectors for the middle view and the graphical view as for velocity.

4. Color everything as usual: cyan, magenta, orange for position, velocity, acceleration. This applies to all vectors, traces, and graphs.
5. With a check box, make a data table available that prints out time, position, velocity, acceleration of the shm and is updated continually during the motion.
6. Have PLAY/PAUSE button and Step button.

2001.09.20 Hans Laue