2.02.07 (7-1-2007) Moved grid lines down to meet floor at y=0 Added bold lines every 5 meters in grid node 2.02.04 (6-30-2007) Measuring tape location is reset properly Fixed: zero-point potential checkbox doesn't reset properly Added grid reset feature Fixed: path record feature doesn't reset properly Fixed: pie chart "show with thermal" feature doesn't reset properly Fixed: "show background" feature doesn't reset properly Fixed: "stickiness" slider doesn't reset properly Fixed: "edit skater" advanced panel doesn't collapse on reset Fixed: "friction" advanced panel doesn't collapse on reset 2.02.03 (6-29-2007) Made charts disappear on simulation reset Reset button also resets simulation speed 2.02.02 (6-25-2007) Added height and speed readouts to path readouts Added cursor hand to path points and readouts 2.01.13 (6-9-2007) Fixed: If the skater is on the floor when gravity changes to 0.0, floor persists in space Fixed: Performance degradation during playback in space 2.01.12 (6-9-2007) Removed "Return skater to x=... y=..." button. Made the red-dot the value used for determining when the skater is offscreen: -for showing the "return skater" button in the play area -for determining whether a "return skater" location has failed, and the skater should be moved to the initial location 2.01.11 (6-9-2007) Set "Reset Skater" button to move the skater to the default location. Added "Return Skater" button to move to the last set restore point. 2.01.10 (6-8-2007) Fixed: Adding a skater with 'A' was broken Fixed: On the E vs. T graph, only one “pause” button should be visible at a time, other button should be grayed out and read “record” or “playback”; it is confusing to see 2 pause buttons at once Fixed: The playback button should be enabled during record; when pressed during recording, it should reset the playback timer and start playback. Moved renderer selection to a right-click menu Right-click on the chart to select the renderer controls. 2.01.09 (6-8-2007) Added developer controls for choosing E vs. T renderer. -You should always leave "buffered" on, unless comparing to "Jfreechart" renderer -The main 2 renderers to consider on are "Piccolo" and "Direct (immediate)" o "Piccolo" does layering correctly o "Direct (immediate)" sometimes interleaves layers, but has higher performance (may not be a concern in this application) -Use the "Show Regions" checkbox to see differences in painted regions 2.01.08 (6-8-2007) Changed recording max time from 50 sec to 20 sec. Readouts on E vs. T plot no longer update during "live mode" 2.01.07 (6-4-2007) Added improved time series controls for main window and Energy vs. Time graph If the user grabs the skater during playback mode (whether or not it is paused), it changes to record (or live) mode. Reworded “Record Path” to “Show Path” "Playback" auto-restarts playback timer if already at the end of the sequence. Change of character is correctly recorded and played back. Added an ellipsis for menu items or buttons that pop up a dialog Fixed: On the tracks that open in roller coaster mode, when you right click, you cannot change the mode Fixed: "Bring back the skater" button should have setopaque false for mac Fixed: Dropping the character outside of the visible range, and then pressing "return the character" returns him to the same offscreen location. -This makes it very difficult to retrieve the character. Fixed: Jet pack graphic doesn't update when thrust changes Removed clock icon Fixed: Readout for “show path” follows last point Rewind button is disabled during record and playback. Made simulation continue after recording time runs out Energy vs. Time readouts update even when mode is live, not record Fixed: Planet radio buttons are deselectable Fixed: Gravity shows as negative zero in space Internal changes: -Fixed: Splines are using manual copy methods, should be using serialization 2.01.06 Consolidated "Record Path" and "Pause" buttons in the control panel. Mountains and house now disappear when "show background" is deselected 2.01.05 (5-30-2007) Moved "with thermal" to same line as pie chart Renamed "Plots" panel to "Energy Graphs" Moved pie chart to Energy Graph section Reordered graphs to pie, bar, position, time 2.01.04 (5-30-2007) Skater reorients angle on a bounce (this item appears in the Options menu) Fixed: Something preventing characters from being grabbed near the left side of the screen Removed "Frictionless Landing" option Increased available zoom-in range Fixed: Grid should continue in the –y direction in space, instead of stopping at y=0. Fixed: In space, splines are still being bumped up above y=0 Fixed: Performance issue when friction > 0 Removed duplicated computation in radius of curvature approximation. Fixed: Grid doesn't turn white when slider is used to select g=0. 2.01.03 (5-23-2007) Fixed: Simulation crashes when E vs. T graph is open and Reset is pressed. Fixed: Numerical readouts are difficult to read on E vs T graph when data overlaps text. Increased maximum zoom out range. Fixed: E vs. X graph, data obscures the legend Fixed: E vs. X graph, data falls outside the chart boundary. Fixed: Bar Graph, data obscures the title Fixed: Playback, then pause, then "Slow Motion" shouldn't reset the playback sequence. Fixed: Record button is grayed out during playback. Fixed: Energy vs. X graph doesn't update during playback. 2.01.02 (5-21-2007) Mountains rescale on zoom-out. Zoom in/out has improved performance. Increased extent of grid. Grid axes are now in bold to differentiate from grid lines. Added tests for fallthrough. When joining tracks, whether the resultant track is in "roller-coaster" mode depends on the mode of the larger constituent track. Grid changes color based on location, to make it more visible against dark background. Fixed: Track popup menu sometimes has the wrong initial value for "roller-coaster mode" Bugfixes for Energy vs. Time chart. Fixed: Legend on Energy vs. Position chart bulges when cursor passes through. Fixed: Zoom buttons are reversed on Energy vs. Position chart. Added a horizontal zoom for Energy vs. Position chart. Standardized zoom buttons for Energy vs. Position chart. Fixed: "Copy chart" copies images of zoom buttons. Fixed: Bar Graph doesn't show negative values well. Fixed: Slow response time for zoom in/out on Bar Graph. Fixed: When zooming out the Bar Graph, Thermal energy doesn't scale properly. Fixed: Measuring tape doesn't scale during zoom in/out. Fixed: Floor still exists in space. Moved "Clear Heat" button from pie chart panel to above Friction Slider. Removed "Clear Heat" button from Friction advanced panel. Moved "Choose Character" button higher in the control panel. Fixed: Pressing "Playback" no longer requires pressing "Rewind" in advance. Fixed: Sometimes the last point in a recording is omitted on playback. Added a red record button. Changed record button text to REC Removed extraneous "Go" button in the playback panel area. Fixed: Zero-point potential's location is not recorded and/or played back Fixed: Floor graphic doesn't update correctly during playback. 2.01.01 (5-10-2007) Test build process. 2.01 (5-10-2007) Same as 2.01.00 2.01.00 (5-10-2007) Same as 2.00.02 2.00.02 (5-5-2007) Changed the name of the Return Skater button under Reset to Return Character. I could also easily make this match the name of the particular skater, as in the "Return Character" button in the play area. Bugfix: When you choose a character and then Reset, the Skater doesn't look the same. For example, he is very tiny after using the ball. And kind of sideways after the bug. Added "Clear Heat" button in pie chart control panel. Made "Clear Heat" buttons become disabled when the system's thermal energy is zero. Added user-presentable "Tracks" menu. 2.00.01 (5-4-2007) Fixed slider to have range that spans all characters Workaround for AbstractValueControl to repeatedly call setValue() without performance degradation 2.00 same as 1.05.28 1.05.28 (5-3-2007) Moved energy error notification enable/disable to options menu. Moved track 1.5 meters to the right so it doesn't look like it's sitting on the mountain. Switched gravity slider to use LinearValueControl, changed looks slightly. 1.05.27 (5-1-2007) Changed default stickiness to 0.9 and bounciness to 0.6. Added a threshold to prevent tiny bounces (if v/(g*dt) < threshold, track is grabbed) 1.05.26 (4-27-2007) Made it so tracks remain a certain threshold above ground (10 cm); to make it more difficult to direct the skater underground. Bugfix: if skater moves beneath ground, he is instantly transported above ground. The ball character should be slightly larger than the dots that appear in record path (or make the dots appear behind the ball). >>This is true at default zoom. Bugfix: When you zoom out, the area that you cannot play on gets bigger (because the ground gradually takes up 1/2 of the screen). Bugfix: roller-coaster mode isn't being saved/loaded correctly. Added "skater restore point" to file save/load to be able to share initial conditions. Toned down the colors on bulldog skateboard. Reduce the length of the bulldog skateboard by about 15% so that his skate board is the same size as the PhET guy’s. Made the bug about ¼ to 1/3 the length of his board, and made his board the same size as the PhET skater. Made the proportions of all the possible skaters accurate in the Choose Character menu. Added an option under Edit Skater to enable "Frictionless Landing" in which the perpendicular part of velocity is not converted to thermal. >>Probably what we want here is if the incident angle is less than greater than 45 degrees, it should be a hard landing (normal velocity converted to thermal) , otherwise "frictionless landing". Bugfix: a bounciness of 1.0 and a stickiness of anything less than 1 thermo energy is reduced on a bounce eventually acquiring a nice huge negative thermo energy. 1.05.25 (4-26-2007) Added restore point, so when user presses "Return Skater" or "Bring Back..." it is placed in the last location the user specified. This information is cleared when "Reset" is pressed. Reduced the radius for track autoconnect. 1.05.23 (4-24-2007) Testing build process. 1.05.22 (4-24-2007) Fixed a bug in playback/record, file save/load, and test running that caused the simulation to crash. Workaround for file extensions in Java Web Start save/load. 1.05.20 (4-23-2007) Fixed text for record button (previously said "Record Path") Added roller coaster mode to new physics implementation Fixed Skater edit control: added "restore defaults", moved bounciness control Skater starts on the track in the default case (to avoid friction); if the user has moved or edited the track, skater starts at previous position. Bugfix: Bar chart should update during playback Changed default value for "Show Thermal" in pie chart to be off Added ability to disable track "auto connect" by holding Ctrl key during drag Bugfix: Track control point doesn't jump to attachment point during proposed match 1.05.19 (4-11-2007) Bugfix in playback/record. 1.05.18 (4-10-2007) Added ball graphic Wired up bounciness control Converted old tests to new format. Track bumps up on mouse release when beneath ground Added energy error indicator Bugfix: running tests with a non-default character, dimensions & character don't match. Bugfix: Thrusting while on track with friction enabled causes incorrect energy behavior (total energy is conserved, thermal energy fluctuates) 1.05.17 (4-4-2007) Added a test case. 1.05.16 (4-3-2007) <14173> Added skater graphics. Bugfix: Tests wouldn't launch 1.05.15 (3-31-2007) Cars (& similar objects) have been removed since they are self-powered. Removed unused image files Shrank the bulldog to 1/3 current size. Reworded “Bring Back Skater” to “Bring Back [character name]” Fixed: Character falls through the track sometimes at high speeds. (Still falls through sometimes at combinations of large speeds & large curvature) 1.05.14 (3-31-2007) Fixed: The very right hand 1/2 inch or so of image is solid color on earth/space. (aspect ratio problem) Added character selection dialog ("Choose character" from control panel) 1.05.13 (3-30-2007) Fixed: "Press arrow keys to add thrust" should disappear after thrusting. Changed default track graphics. 1.05.12 (3-30-2007) [14118] Fixed: Memory leak in EnergySkateParkSplineListAdapter Fixed: Dragging skater should clear heat Fixed: Return skater should clear heat Fixed: Pie chart button should be enabled on ground Fixed: Bar chart should clear heat when paused Fixed: Ground should come back when dragging gravity slider above 0.0 Added editor for track graphics (right click track -> Edit) Made it easier to grab PE=0 line Added gradient for sky on earth. 1.05.11 (3-29-2007) Many bugfixes for new physics. Fixed graphics for direction skater is facing. Added special friction for ground (friction for all tracks, averaged with skater friction?) Fixed: Return skater in space resets gravity. Skater cannot be dragged underground. Fixed: Skater should point at track while dragging. 1.05.07 (3-4-2007) <13466> Added 1-d test case. 1.05.06 (2-28-2007) Added 1-d track collisions & reattachment. 1.05.04 (2-18-2007) Added tests for L&F 1.05.03 (2-14-2007) "Save" also saves skater's rotation, position, etc. Added tests for motion. Added a test for new spline mechanics. 1.05.02 (2-5-2007) When potential energy is negative, pie chart is invisible and pie chart button is disabled. After the maximum number of history points (max=100), history points start disappearing. History points are now purple rather than yellow. Control points can no longer be dragged below ground. Added a control for whether normal velocity should convert to parallel velocity, or convert to thermal during a landing. Removed negative potential energy (black). 1.05.01 (1-17-2007) Fixed a bug in Normal Force computation. Fixing the bug in Normal Force computation caused spurious off-track velocities (since buggy normal forces were directed slightly into the track). -Introduced a velocity threshold that has to be met before flying off the track. 1.05 (1-17-2007) Posted on main site. 1.04.01 (1-12-2007) Bugfix: When in Gravity=0.0, skater gains energy when grabbing on to track and loses energy when stopping at end of track. 1.04 (1-10-2007) Bugfix: Launch fails on European language format ("0,00" parse error") 1.03 (12-12-2006) Posted on the main site as 1.03 1.02.27 (12-11-2006) Bugfix: The performance degrades significantly after 10 minutes or so. Added a temporary workaround that keeps the recorded data under a manageable size without influencing the rest of the simulation. The user can record about 45 seconds of data, the system automatically switches to live (non-record) mode when this is filled up, the user then has to manually press "clear" before they can record a different dataset. 1.02.26 (12-2-2006) Added zoom buttons to bar graph. Bugfix: The record path data stays the same size relative to the man so is unreadable when zoomed out. Bugfix: Resizing the window shouldn't reset zoom. 1.02.25 (12-1-2006) Bugfix: When you have more than one guy (after hitting A) the Return Skater pop-up feature isn't working well. 1.02.24 (12-1-2006) Bugfix: There shouldn't be a negative potential energy entry in the energy-position graph. 1.02.23 (12-1-2006) Bugfix: Sometimes the normal force is negative when it should be zero. Bugfix: Sometimes when paused, 'go' is unavailable. Added pause message to play area for when 'go' is paused (instead of just when 'record' is paused.) Bugfix: When energy vs position graph is copied, if the data is off-the-chart, it comes up bogus. Relabeled the "show pie chart" checkbox to "show pie chart". Added a legend item for black potential energy. Bugfix: Energy vs time chart has 'java application window' covering up the good parts. This window has a bigger default height. Bugfix: Reset from space causes crash. Added more key options: 'a' for add skater, 'd' for delete, 'r' for remove Added an onscreen zoom button. Moved pie chart legend to top-right. Bugfix: In E vs. T graph, rescaling the y axis shouldn't center on the E=0 axis. Bugfix: For E vs T. graph (and maybe other graphs), should have moving man style zoom buttons. Bugfix: The skater falls through the ground outside the range -10 to +10 Extended the range of the ground to -100 to +100 (handles most cases with current camera zoom) 1.02.22 (11-29-2006) Bugfix: when entering playback mode, floor track duplicated. Bugfix: Record, pause, switch location, go should remain in the newly selected location. Now 'Go' doesn't initialize to the last-recorded-state before starting. Bugfix: Pausing 'go' then pressing 'playback' should have 'slow' enabled. Energy vs. Position graph 'copies' stay in front of the simulation frame. Energy vs. Position graph changed text-labeled zoom buttons to magnifying glass icons. 1.02.21 (11-29-2006) Removed the floor from outer space. Stretched outer-space graphic to fit screen without floor graphic. Set color of ground to match location (i.e. earth is green, moon is gray). The skater points his feet toward the closest track when the user is dragging him. Changed "Friction>>" to "Track Friction>>" for the friction button. Changed "Record Path" from a checkbox to a button. "Record Path" was moved below the tool checkboxes. Clear thermal when manipulating the skater. The energy dissipates in a smooth animation, not all at once. Resetting the skater clears the thermal energy. Changed "Hide Thermal" to "Show Thermal" for the pie chart controls. Show Thermal is now default for pie chart. Bugfix: The values for energy show up under the yellow record dots so you can't read the values. Bugfix: Reset does not get rid of the tape measure if you have it out. Bugfix: The potential Energy Reference line is Red but potential energy on the graphs is blue. 1.02.20 (11-15-2006) Removed logo panel for users with screen height<=768 pixels. Bugfix: after record and playback, the rocket graphic doesn't appear 1.02.19 (11-15-2006) Bugfix: potential energy (pie chart) is wrong when PE=0 line makes PE negative Made pie chart piece black for negative potential energy. Bugfix: reset sometimes causes a crash. 1.02.18 (11-15-2006) Bugfix: Skater with mass of 1kg gets stuck a lot. 1.02.17 (11-15-2006) Bugfix: fixed a bug introduced in 1.02.16 that caused thrust to behave incorrectly in free fall and spline mode. 1.02.16 (11-15-2006) Bugfix: When the interacts with the track, energy is not conserved. Now energy is conserved when possible, unless the user has added energy to the system. 1.02.15 (11-15-2006) Improved spline traversal code: more accurate representation of normal force small bugfixes & parameter edits Bugfix: There is an error with friction on the ground, and falling through the ground. Bugfix: Deleting a control point during spline traversal crashes the application. Bugfix: Gravity value doesn't change sometimes after a record/playback. Bugfix: Identified a problem that caused skater to get stuck on the high part of his spline traversal, or in low gravity. 1.02.14 (11-10-2006) Bugfix: History buttons are displaying total energy without thermal, and calling it total. -Added a thermal energy readout, and fix the total energy value to reflect all energy (not just mechanical energy). Reduced maximum allowed friction. Removed keypress focus from friction control (so it won't change while using thrust). Bugfix: Skater rotates back and forth quickly when at the bottom of a potential well (with friction). Skater can traverse the track while underground. Relabeled "Slow Motion" to "Playback Slow" Bugfix: After some combination of recording and playback, the track graphic becomes dissociated from the skater. -The skater will continue to traverse the path where the track used to be, even after it has been dragged. -This solution is a bit of a hack, not elegant, passes tests, but not guaranteed accurate. 1.02.13 (11-10-2006) Set the bounciness to correspond to the bounciness slider. Set the minimum mass of the skater to 1.0 kg. Fixed a bug that caused save/load to fail sometimes. 1.02.12 (11-8-2006) Bugfix: When you move from space to earth the "use arrow keys to thrust" stays up. Bugfix: When I pulled up energy vs time graph, and messed around with pausing, using cursor, and trying to go again ... it got confused. (Right now I can't get the guy to start moving again ... even when I hit Reset.) Added friction for bounces, when friction is enabled. Added coefficient of restitution as a nonlinear function of friction coefficient. Added insurance that the skater won't pass through a spline while in free-fall. Removed some bogus collision code (for handling ends of spline). Added code that prevents the skater from bouncing back and forth centered on a track. Added save/load for splines & skaters. Added roller-coaster mode (sticky tracks). Deleted some spline traversal code that caused the skater to get stuck. 1.02.11 (11-3-2006) Made the "Return The Skater" button pop up when the skater is partially offscreen (rather than when he is completely offscreen). Bugfix: The man jiggles around when on a nearly horizontal piece of track. 1.02.10 (11-3-2006) Added a "Step" button to playback, live, and record modes. Added another mechanism to reduce energy errors in spline traversal mode. This prevents the problem where the skater gets stuck at a high point at slow velocity. 1.02.09 (11-2-2006) Improvements in spline traversal. Consolidate top/bottom splines. Rewrote Track Toolbox to work at different scales. Track Toolbox code is more elegant. Fixed: Dragging a control point of the skater's track can cause him to freeze. Fixed: Track graphic is stopping one segment before the end of the track. 1.02.08 (10-25-2006) Removed track graphic at ground-level. Added friction to ground. Added preliminary collision code to avoid getting stuck in a track (needs more testing). 1.02.07 (10-18-2006) Bugfixes in old references to FreeSplineMode (1st version) 1.02.06 (10-18-2006) Added improved frame sizes for deployment Added tests Bugfix in spline traversal (if error is too high, rollback change, don't use global energy) 1.02.05 (10-18-2006) Rewrote spline traversal physics. Added tests. 1.02.03 (10-11-2006) Added smoothing for spline traversal (to smooth out jerkiness e.g. at bottom of parabola) Added code so the skater can fall off of spline when his velocity dotted with the unit normal of the segment is positive. Found an instance of unconserved energy and remedied it. Bugfix: pressing go after playing back a sequence inverts the angle. Bugfix: Jet pack isn't visible after reset. Bugfix: When I go to space or set gravity to zero, if I don't use the arrows before I hit RESET, the arrow keys don't work. For example, if you go to space and then hit Reset, the arrows work the far right slider. Bugfix: If you use the space simulation, and change to gravity and back, sometimes (can't be sure how exactly) the thruster/jets don't show on the skater in space mode, though he does move as if they are firing. Seems like the simulation of his jet pack is not quite getting reset. 1.02.02 (10-11-2006) Bugfix: When he's stationary and the track is moved he doesn't fall. Bugfix: When he's oscillating on the track and I lift the track up the skater can end up oscillating back and forth, as if a track was there, but it's not really there. Fixed a memory leak. Bugfix: 'Reset Skater' turns him upside down sometimes. Bugfix: Reset doesn't work any more ... the skater is just frozen (and the red dot doesn't go with him). Bugfix: After a long time, the man is stopped and when I tried to grab him, all I could move around was the little red dot, not the actual skater. 1.02.01 (10-11-2006) Revision of dynamics to address problem at the bottom of a potential well. 1.02 (7-10-2006) Made the grid overlay x-axis match the Energy-Position plot's x-axis. 1.01 (7-10-2006) Posted on main site. 0.00.28 (6-8-2006) Updated gravity controls. Bugfix: Performance degrades when showing history points. Bugfix: Grid intercepted mouse clicks. 0.00.26 (6-8-2006) Fixed gravity controls. Bugfix: readout of history points is incorrect. 0.00.25 (6-7-2006) Added an optional overlay grid. Fixed a bug in the wiggle me. 0.00.24 (6-6-2006) Bugfix in the build process (wouldn't run under 1.4) 0.00.23 (6-6-2006) Renamed JNLP Launch title from Energy Sk8r to Energy Skate Park Brightened the skater image. Performance bugfix. -Version 0.00.22 (6-2-2006) Decreased the sensitivity of the 'return the skater' button; skater has to be completely offscreen (not partially offscreen) Moved the pie chart legend to the bottom of the page. Added a jet pack graphic which points the correct direction. Bugfix: Background color doesn't match image color for different screen sizes. Reduced download size by 120kb (removal of unused images). Added a wiggle me hint for using the arrow keys to apply thrust; the hint appears when choosing zero-gravity first time. Added zoom in/out for energy-position plot. Bugfix: Setting record, then live, then record resets to last record state. -Changes for 0.00.21 (5-29-2006) Added a button to return the skater when he has flown out of view. Moved friction & clear heat controls to an expandable advanced panel. Removed the text field and numerical tick labels from friction slider; labeled extrema "none" and "lots" Bugfix: Clear button erroneously shows 'this simulation is paused' when it is not. Bugfix: The measuring tape's initial readout is incorrect. Added tool icons. Increased the initial and "return" height of the skater; increased the initial track to ensure a smooth first ride. -Changes for 0.00.20 Changed the look and feel to platform specific. Bugfix: The scale for the readings on the path data is unreadably huge. Made the view of history point data toggle-based, so 2 can be visible at once. Added a warning box to the reset button that says, Are you sure you want to reset? Bugfix: Removed the ability to drag (pan/zoom) the bar graph graphics. Removed the minimize button from the bar chart. Removed the "Total Energy" entry from the pie chart legend. Added a "Clear Heat" button to the bar graph window. Bugfix: When minimizing and restoring the window, the chart & graph windows don't restore their state. Bugfix: The charts all flash up on the screen for a second during startup. Added a helmet graphic. -Changes for 0.00.19 (5-14-2006) The simulation is now titled 'Energy Skate Park' The skater's potential energy is now zero when he's on the ground (by default). The skater cannot be dragged outside the window, or below ground. -Changes for 1-2-2006, 0.17 “Play” has been changed to “Go” for clarity. Add a movable “zero-point potential energy” graphic Add a clear button to e vs t graph in skater. Remove "minimize" button from e vs t in skater. Background is on by default Improved backgrounds a bit (tone down, position properly) -Changes for 12-23-2005, 0.15 Paused shows up in the play area when skater is paused. Renamed “Live” to “Play” Radio buttons match slider values. (all off when no exact location). Energy vs. Time chart comes up recording. Added color code legend for pie chart. Energy vs Position graph has a color-coded legend. Energy vs Position graph doesn't fade during pause. Renamed “Coefficient of Restitution” to “bounciness” Reset starts module running (not paused) Reset button changes the values in “edit skater” Save graphs (e.g. to compare friction on to friction off). -Changes for 11-17-2005, 0.13 Fix playback panel button sizes for 1024x768. Move Energy vs position button near other plot buttons. Rename 'show plot' to Plot Energy vs Time Rename 'reset skater' to 'return skater' Energy Vs. Position plot: fix horizontal range rename 'title' to 'energy vs. position' horizontal axis label Earth background is kPhet Make object mass switchable. Add a control for coeff of restitution. Fix horizontal range on Energy vs Position graphs. Turned model and view upside down. Paint like Jupiter/Earth/Moon/Space. Change Locale (background & gravity). The ground can be driven on and only bounced off. -Changes for 11-14-2005, 0.10 Added performance enhancements for energy-position graph Added a vertical location indicator in energy-position graph Bugfix: A bounce entails a loss of energy (which I didn't intend). Add coefficient of restitution. -Changes for 11-8-2005, 0.09 Improved performance on energy vs. position plot. Data points fade on the energy vs. position plot. Gravity is user-settable. Better center of mass for the skater. -Changes for 11-7-2005, 0.08 1. Fixed a bug in the friction update 2. Switched to Runge-Kutta 4th order differential equation solver. 3. Max selectable coeff of kinetic friction is 0.04 4. Added plot of energy vs position (experimental, not optimized). 5. Move labels below bar chart. 6. Colorize bar chart labels. 7. Added thermal energy to plot 8. Fixed a bug that prevented the splash screen on startup. 9. Minimized download size. -Changes for 0.07 and earlier Record history dots Measuring tape Man can be re-centered without restarting application. pie chart Area is proportional to energy (not Diameter)