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 Author Topic: Using tracker to gather evidence of speed of Ferrari was at 216? or 140 km/hr?  (Read 15951 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
lookang
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 « Embed this message on: May 16, 2012, 10:28:00 am » posted from:SINGAPORE,SINGAPORE,SINGAPORE

What evidence(s) are there of the speed of Ferrari was traveling at 216 km/hr?
Using Tracker physics comes alive and becomes relevant to everyday life

http://weelookang.blogspot.com/2012/05/what-evidence-of-speed-ferrari-was.html

sharing the source trk and video here

Ferrari 599 GTO crashed a Taxi causing 3 dead, 2 injured in Bugis S'pore - 12May2012

 video analysis using tracker on Ferrari & taxi crash at Bugis Rochor Junction dated

using a video found here

Step 2: save the video into the computer

Step 3: use tracker http://www.cabrillo.edu/~dbrown/tracker/ to open the video file

1. taxi camera is stationary for the duration of the 0.3 seconds the Ferrari sped across

2. the height of the traffic light post is approximately 2.0 m from base to green light center

3. the video is properly time-frame as 30 frame/seconds as default in the video data, and read correctly by tracker.

4. the Ferrari is traveling at constant acceleration = 0 m/s^2

track the front of the Ferrari.

Step 5: Make roughly 8 to 9 points as shown

 using tracker to trace the motion of the car

Step 6: .Analyze the speed

which is roughly 60 m/s from as evidence from the

6.1 s vs t graph,

 linear fit x = 60.178*t + -13.821 where a = 60.178 which means the average velocity assuming a constant velocity motion

linear fit x = 60.178*t + -13.821
by comparing coefficient to constant acceleration equation x = u*t + x0
roughly u = 60 m/s

6.2 v vs t graph
statistic mean
v average = 60 m/s

 data tool notice the mean for x is 6.097E1 which means 60.97, another evidence of average velocity

Conclusion:

when converted to km/hr,
v = 60*3600/1000 = 216 km/hr = 210 km/hr ( round down 2 significant figures) = 200 km/hr ( 1 significant figure).

Claim:

The vehicle is likely to be traveling at speed of 200 km/hr, given the evidences and assumptions made in the analysis.

Question:

What do you think ??

Source of errors:

1. moving source camera and some parallax error taxi camera was not stationary for the duration of the 0.3 seconds the Ferrari sped across.

2. the height of the traffic light post is not 2.0 m from base to green light center

3. the source of the video could not be verified in the time frame used to capture the video, and the time-frame may not be 30 frame/seconds, though it is likely to be correct.

Physics & Science lesson learn could be:

• Using current affairs to educate the children on everyday physics and making physics relevant.

• using evidences to justify claims.

Morale lessons caught could be:

• Don't drive recklessly.

• Don't beat red lights.

• Be responsible

Disclaimer:

This post is made with the best intentions to share good active learning practices in physics education, any offenses taken please leave a comment, i will amend the post or/and to remove offensive content if any.

The mass media media corp 5 news also reported on the accident.

 trackerF04.png (324.91 KB, 1280x994 - viewed 1095 times.) *** There are 2 more attached files. You need to login to acces it! « Last Edit: May 17, 2012, 03:59:46 pm by lookang » Logged
lookang
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 « Embed this message Reply #1 on: May 16, 2012, 10:16:32 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE

new measurements suggests it is only 110 km/hr

Ferrari 599 GTO crashed a Taxi causing 3 dead, 2 injured in Bugis S'pore - 12May2012

 updated with inputs on length of FERRARI car travel to be 13.0± 1 m instead of the older assumption of 10 m

 updated video analysis using tracker on Ferrari & taxi crash at Bugis Rochor Junction suggests 110 km/hr

 using Google map to locate and make sense of the actual video scene, a bit of an attempt to measure the distance on the map but the length is too small for accurate distance measurement of 10 m

 Google map street view from the taxi camera position

 video analysis using tracker on Ferrari & taxi crash at Bugis Rochor Junction dated

using a video found here http://www.youtube.com/watch?v=S80bDrxrCiI&feature=related

Step 2: save the video into the computer

Step 3: use tracker http://www.cabrillo.edu/~dbrown/tracker/ to open the video file

 new estimates of length of car travel in video is now 13.0 ± 1 m , still the cab bumper can be fitted by 1.81 m length

reason for readjusting the length of car traveled, results from a discussion with physics education expert D, Wong who suggested using nokia maps

to estimate the length of car in the video ( we measure from 2 white line of the
pedestrian walking to the center of the junction box. )

 to estimate the length of car in the video ( we measure from 2 white line of the pedestrian walking to the center of the junction box. ) show about 13 ± 1 m, against the map scale on the bottom right 10 m

 using tracker, the measurement of length is done easily using calibration tape (length to be measured) and stick (10m)

 distance traveled by car is roughly 10 m and bumper of taxi is roughly 1.8 m (see diagram)

1. taxi camera is stationary for the duration of the 0.3 seconds the Ferrari sped across

2. the height of the traffic light post is approximately 2.0 m from base to green light center

3. distance traveled by car is roughly
13 ± 1 10 m and bumper of taxi is roughly 1.8 m (see diagram)

4. the video is properly time-frame as 30 frame/seconds as default in the video data, and read correctly by tracker.

5. the Ferrari is traveling at constant acceleration = 0 m/s^2track the front of the Ferrari.

Step 5: calibrate pixels in video with known lengths, improved strategy after discussion on Facebook distance traveled by car is roughly
13 ± 1 10 m and bumper of taxi is roughly 1.8 m.

Step 6: Make roughly 8 to 9 points as shown

 Make roughly 8 to 9 points as shown

 using tracker to trace the motion of the car

Step 7: .Analyze the speed

7.1 s vs t graph, which is roughly 39.23 m/s from as evidence from the

 linear fit x = 39.231*t + -0.352 where a = 39.231 which means the average velocity assuming a constant velocity motion

 linear fit x = 30.187*t + -0.271 where a = 30.187 which means the average velocity assuming a constant velocity motion

 linear fit x = 60.178*t + -13.821 where a = 60.178 which means the average velocity assuming a constant velocity motion

linear fit x = 60.178*t + -13.821by comparing coefficient to constant acceleration equation x = u*t + x0roughly u = 60 m/s

7.2 v vs t graph statistic mean v average = 39.75 30(wrong estimate) 60 (wrong estimate) m/s

 data tool notice the mean for x is 3.975E1 which means 39.75, another evidence of average velocity

 data tool notice the mean for x is 3.059E1 which means 30.059, another evidence of average velocity

 data tool notice the mean for x is 6.097E1 which means 60.97, another evidence of average velocity

average it out = (39.231+39.75)/2 = 39.5 m/s

Error Analysis:

assume average v = d/t

error analysis suggests,

Δv/v = Δd/d + Δt/t

using estimates of

Δd = 1 m (estimate from nokia map), d = 13 (nokia map)

Δt = 1/30 (from framerate) , t = 0.30 (from tracker)

v = 140 m/s

therefore, Δv = 0.18*v = 26
30 m/s (1 sign figure)

Conclusion:

when converted to km/hr, v = 39.5*3600/1000 = 142 km/hr 140 ± 30 km/hr ( follow the order of magnitude of the error)

Claim:

The vehicle is likely to be traveling at speed of 140± 30 (current best estimate, as of 17May2012)

Question:

What do you think ??

Source of errors:

1. moving source camera and some parallax error taxi camera was not stationary for the duration of the 0.3 seconds the Ferrari sped across.

2. the distance traveled by the car may not be corrected measure, thus, a nokia map was used to check.

3. the height of the traffic light post is not 2.0 m from base to green light center

4. the source of the video could not be verified in the time frame used to capture the video, and the time-frame may not be 30 frame/seconds, though it is likely to be correct.

Physics & Science lesson learn could be:

• Using current affairs to educate the children on everyday physics and making physics relevant.

• using evidences to justify claims.

• science knowledge is socially constructed with newer evidences suggesting better ways of explaining the phenomena.

Morale lessons caught could be:

• Don't drive recklessly.

• Don't beat red lights.

• Be responsible

Open Content Sharing of Educational resources creative commons attribution:

the video, trk files are downloadable at NTNU java Forum http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2447.0 , available to registered users of the forum, registration is FREE.

trackerF04.png (324.91 KB, 1280x994 )

videoplaybackwee.trk (14.38 KB )

videoplaybackwee.zip (2382.25 KB ) based on incorrect light post height

videoplaybackwee01.zip (2594.63 KB ) based on incorrect length of car traveled in video evidences and measurements

videoplaybackwee02.zip (2996.85 KB) based on better estimates of length of car travel

Disclaimer:

This post is made with the best intentions to share good active learning practices in physics education, any offenses taken please leave a comment, i will amend the post or/and to remove offensive content if any.

 *** There are 1 more attached files. You need to login to acces it! « Last Edit: May 17, 2012, 03:58:22 pm by lookang » Logged
Fu-Kwun Hwang
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 « Embed this message Reply #2 on: May 17, 2012, 11:45:09 am » posted from:Taipei,T'ai-pei,Taiwan

Nice job. Keep up the good work! :-)
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lookang
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 « Embed this message Reply #3 on: May 17, 2012, 03:49:04 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE

newer measurement made on the path of travel suggests 140 +- 30 km/h
thanks to D wong for stimulating discussions.

Step 2: save the video into the computer

Step 3: use tracker http://www.cabrillo.edu/~dbrown/tracker/ to open the video file

 new estimates of length of car travel in video is now 13.0 ± 1 m , still the cab bumper can be fitted by 1.81 m length

reason for readjusting the length of car traveled, results from a discussion with physics education expert D, Wong who suggested using nokia maps

to estimate the length of car in the video ( we measure from 2 white line of the
pedestrian walking to the center of the junction box. )

 to estimate the length of car in the video ( we measure from 2 white line of the pedestrian walking to the center of the junction box. ) show about 13 ± 1 m, against the map scale on the bottom right 10 m

 using tracker, the measurement of length is done easily using calibration tape (length to be measured) and stick (10m)

 distance traveled by car is roughly 10 m and bumper of taxi is roughly 1.8 m (see diagram)

1. taxi camera is stationary for the duration of the 0.3 seconds the Ferrari sped across

2. the height of the traffic light post is approximately 2.0 m from base to green light center

3. distance traveled by car is roughly
13 ± 1 10 m and bumper of taxi is roughly 1.8 m (see diagram)

4. the video is properly time-frame as 30 frame/seconds as default in the video data, and read correctly by tracker.

5. the Ferrari is traveling at constant acceleration = 0 m/s^2track the front of the Ferrari.

Step 5: calibrate pixels in video with known lengths, improved strategy after discussion on Facebook distance traveled by car is roughly
13 ± 1 10 m and bumper of taxi is roughly 1.8 m.

Step 6: Make roughly 8 to 9 points as shown

 Make roughly 8 to 9 points as shown

 using tracker to trace the motion of the car

Step 7: .Analyze the speed

7.1 s vs t graph, which is roughly 39.23 m/s from as evidence from the

 linear fit x = 39.231*t + -0.352 where a = 39.231 which means the average velocity assuming a constant velocity motion

 linear fit x = 30.187*t + -0.271 where a = 30.187 which means the average velocity assuming a constant velocity motion

 linear fit x = 60.178*t + -13.821 where a = 60.178 which means the average velocity assuming a constant velocity motion

linear fit x = 60.178*t + -13.821by comparing coefficient to constant acceleration equation x = u*t + x0roughly u = 60 m/s

7.2 v vs t graph statistic mean v average = 39.75 30(wrong estimate) 60 (wrong estimate) m/s

 data tool notice the mean for x is 3.975E1 which means 39.75, another evidence of average velocity

 data tool notice the mean for x is 3.059E1 which means 30.059, another evidence of average velocity

 data tool notice the mean for x is 6.097E1 which means 60.97, another evidence of average velocity

average it out = (39.231+39.75)/2 = 39.5 m/s

Error Analysis:

assume average v = d/t

error analysis suggests,

Δv/v = Δd/d + Δt/t

using estimates of

Δd = 1 m (estimate from nokia map), d = 13 (nokia map)

Δt = 1/30 (from framerate) , t = 0.30 (from tracker)

v = 140 m

therefore, Δv = 0.18*v = 26
30 m/s (1 sign figure)

Conclusion:

when converted to km/hr, v = 39.5*3600/1000 = 142 km/hr 140 ± 30 km/hr ( follow the order of magnitude of the error)

Claim:

The vehicle is likely to be traveling at speed of 140± 30 (current best estimate, as of 17May2012)

Question:

What do you think ??

Source of errors:

1. moving source camera and some parallax error taxi camera was not stationary for the duration of the 0.3 seconds the Ferrari sped across.

2. the distance traveled by the car may not be corrected measure, thus, a nokia map was used to check.

3. the height of the traffic light post is not 2.0 m from base to green light center

4. the source of the video could not be verified in the time frame used to capture the video, and the time-frame may not be 30 frame/seconds, though it is likely to be correct.

Physics & Science lesson learn could be:

• Using current affairs to educate the children on everyday physics and making physics relevant.

• using evidences to justify claims.

• science knowledge is socially constructed with newer evidences suggesting better ways of explaining the phenomena.

Morale lessons caught could be:

• Don't drive recklessly.

• Don't beat red lights.

• Be responsible

Open Content Sharing of Educational resources creative commons attribution:

the video, trk files are downloadable at NTNU java Forum http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2447.0 , available to registered users of the forum, registration is FREE.

trackerF04.png (324.91 KB, 1280x994 )

videoplaybackwee.trk (14.38 KB )

videoplaybackwee.zip (2382.25 KB ) based on incorrect light post height

videoplaybackwee01.zip (2594.63 KB ) based on incorrect length of car traveled in video evidences and measurements

videoplaybackwee02.zip (2996.85 KB) based on better estimates of length of car travel

Disclaimer:

This post is made with the best intentions to share good active learning practices in physics education, any offenses taken please leave a comment, i will amend the post or/and to remove offensive content if any.

The mass media media corp 5 news also reported on the accident.

 *** There are 1 more attached files. You need to login to acces it! « Last Edit: May 17, 2012, 03:58:42 pm by lookang » Logged
lookang
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Posts: 1796

http://weelookang.blogspot.com

 « Embed this message Reply #4 on: May 19, 2012, 10:31:56 pm » posted from:SINGAPORE,SINGAPORE,SINGAPORE