Deadlines Fourth Homework Analyzing Video Due Thursday Sept 15 th This week 15 points 10 points if late Fifth Homework Path of Action Analysis Due Thursday Sept 29 th Two weeks ID: 407836
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Upcoming Deadlines
Fourth Homework (Analyzing Video) Due Thursday, Sept. 15th (This week) 15 points (10 points if late) Fifth Homework (Path of Action Analysis) Due Thursday, Sept. 29th (Two weeks) 15 points (10 points if late) For full schedule, visit course website: ArtPhysics123.pbworks.com
Pick up a clicker, find the right channel, and enter Student IDSlide2
Homework Assignment #4
We will be using a video analysis program called "Tracker" to study motion. Download a copy of the program from the Tracker website:http://www.cabrillo.edu/~dbrown/tracker/Run the Tracker program on your computer, import the video clip of a falling object that you created in the previous homework assignment and analyze the falling motion. This assignment is due by 8am on Thursday, September 15th (this week).Slide3
Homework #4
HorizontalMotionVerticalMotionImage you post on your blog should look something like this.Slide4
Activating your Clicker
* Turn on your clicker.* Enter the channel number or letter for joining this class. Hit Enter/Send key.* Clicker should read AP123KF11* Type in your student ID; hit Enter/Send.Clicker is now ready to use; leave it on.Hit any key to wake the clicker from sleep mode.Slide5
Survey Question
How easy have you found it to use the Tracker software?Pretty easy to useA little confusing but OKFrustrating to useHaven’t tried using it yetNote: You score 1 point of credit for answering survey questions, regardless of your answer.Slide6
Review Question
What’s wrong with the spacings in these drawings of a ball thrown in the air?Vertical spacings wrong; horizontal spacings are OK.Horizontal spacings wrong; vertical spacings are OKBoth vertical and horizontal spacings are wrong.
Actually, the
spacings
are
OK for this path of action.Slide7
Review Question
C) Both vertical and horizontalspacings are wrong.The vertical spacings are too uniform; the motion should slow in as it rises.The horizontal spacings should be uniform but instead they slow out going left to right. Slide8
Madagascar 2 (2008)
Carefully observe the path of action when the plane is in the air.http://www.youtube.com/watch?v=Anflb_oWdgoSlide9
Review Question
This path of action is a parabolic arc.TrueorFalseSlide10
Review Question
False.The arc is shallow when the plane flies off the cliff but very steep after the apex.
Parabolic arc is symmetric about the apexSlide11
Paths ofAction
(cont.)Slide12
Throwing at
an AngleWith no gravity, a thrown object would follow a straight line.Due to gravity, the object falls beneath this line, just as if released from rest.No GravityWithGravity12Frames
4 feet
16 feet
36 feet
24
Frames
36
FramesSlide13
“Shoot the Monkey”
Monkey lets go of the branch the moment he hears the gun fire.Rifle is aimed at monkey’s nose.
Bullet hits the monkey:
Above the nose
On the nose
Below the noseSlide14
“Shoot the Monkey”
B) On the nose.Bullet and monkey fall at same rate so they stay at the same height.
This happens even if the gun aims at an angle.
Bullet and monkey fall at same rate.Slide15
“Shoot the Monkey”
http://www.youtube.com/watch?v=cxvsHNRXLjwSlide16
Speed (1994)
In Speed, a city bus jumps across an unfinished freeway bridge in Los Angeles.Is this jumpunrealistic?Slide17
Speed (1994)
http://www.youtube.com/watch?v=CX6aVa7B2qQSlide18
Speed (1994)
The bus should be in the air for about one second (although in the movie it’s over seven seconds).Missing section is about two bus lengths, which is 80-90 feet. At 65 m.p.h. you travel about 95 feet per second.Slide19
Speed (1994)
Since the bus is in the air for about a second it drops 16 feet so the angle of the bridge would have to be about 10 degrees for the bus to land correctly on the other side.90 feet16 feetPopping a wheelie
does not help!Slide20
Speed (1994)
The film makers did not jump a bus over a gap in a bridge. In fact the gap in this bridge is fake; it was painted in digitally.However they forgot to paint out the shadow on the ground.Slide21
Speed (1994)
This part of the film was digitally painted in.The bus jump is a stunt filmed with a real bus but the gap is fake.Slide22
Speed (1994)
http://www.youtube.com/watch?v=CX6aVa7B2qQSlide23
Maximum Range
Maximum range is at a launch angle of 45 degrees (when air resistance is negligible).RangeHeightSame initial speedsSlide24
Trebuchet
Siege of JerusalemThe trebuchet was the ultimate mechanical siege engine. Developed in the Far East and brought west in the 10th century by the Mongol and Muslim armies.European armies adopted the trebuchet during the Crusades of the 12th
century.
Counterweight lifted by human powered “hamster wheels”Slide25
Mangonel
The mangonel is a simplified trebuchet using a fixed counter-weight.Slide26
Releasing the Projectile
The release mechanism is designed to throw the rock at a 45 degree angle.45ºReleaseSlide27
Importance of Range
Heavy medieval weapons had to operate outside the range of archers (about 200 yards).A trebuchet can hurl stones out to 350 yards, with a launch speed of 130 miles per hour.Slide28
LotR: Return of the King (2003)
http://www.youtube.com/watch?v=7bFTw95pJp8Slide29
Kingdom of Heaven (2005)
Several full-size trebuchets were built for the film “Kingdom of Heaven.”Many more were inserted into the movie by digital effects.Slide30
Tracking and Motion GraphsSlide31
Using Reference
Animator Ken Harris at work, using himself as a model.Visual artists have always used models and reference in their work.One of the most useful tools for the modern animator is the digital movie camera.Slide32
Video Reference & Madagascar 2
http://www.youtube.com/watch?v=GUBEwUvtssESlide33
Horton Hears a Who
http://www.youtube.com/watch?v=ouaspd_dr5oSlide34
Tracking and Motion Graphs
Next LectureAnalyzing Video (Tracker) due Thursday, 9/15 @ 8 AM