3. Test and modification

3.1 Trial Test and Design Modification


Run Number
Run 1
Rerun 1
Rerun 2
Total time of Run
11s10s10s
Total distance of Run
>13m>15m>15.5m
Time for lever to fully release
5s5s5s
Distance car travels while lever is releasing
10m10.5m10.5m
Observations – did car travel smoothly,
straight, always forward, etc?
Smoothly, but turned rightSmoothly, but turned slightly rightSmoothly, but turned slightly right
Did lever / string operate smoothly?
YesYesYes
Filename of video recorded is:  
IMG 0640 RUN 1 IMG 0647 RUN 1 IMG 0651 RUN 2 IMG 0649 RUN 3
For all 3 runs; Modification was made on RERUN 1

Area for improvement (1 only)
Car turned to the right



Possible reason (1 only) 
String wrapped around the rear axle was positioned nearer to the left, meaning that there was more tension force on the left than the right - thus when the level was releasing, the string pulled the rear axel on the left side up, causing the left rear wheel to rise up from the ground, balancing on only the front wheels & right rear wheel, causing it to move to the right.



Modification made (1 only)



String wrapped around the rear axle was positioned nearer to the centre, so that the force (tension) pulling the axle will be balanced, thus the left wheel will not be pulled up from the ground, causing the car to move striaght, instead of moving to the right.

MODIFICATION  (New Google-sketchup)


MG 0646 Modification Video http://youtu.be/D2kWMgAREds
Modification made: String wrapped around the rear axle was positioned nearer to the centre, so that the force (tension) pulling the axle will be balanced, thus the left wheel will not be pulled up from the ground, causing the car to move striaght, instead of moving to the right. 




3.2 Test Data

  1. All relevant measurements of your car (after modification).

Mass of your car 310g

Mass of each wheel (or one of they are all the same) 20g, 11g

Wheel diameter 6cm

Axle diameter 0.3cm

Length of string (power stroke) 25cm

Approx. number of wraps of string 35

Length of lever extension 20cm

Overall length: 25cm

Overall width: 14cm

Overall height: 10cm



  1. Data tables showing the results of all 3 trials.


Run Number
1
2
3
Total time of Run
11s10s
10s
Total distance of Run
>13m>15m
>15.5m
Time for lever to fully release
5s5s
5s
Distance car travels while lever is releasing
10m10.5m
10.5m
Observations – did car travel smoothly,
straight, always forward, etc?
Smoothly, but turned rightSmoothly, but turned slightly right
Smoothly, but turned slightly right
Did lever / string operate smoothly?
YesYesYes
Filename of video recorded is:
IMG 0640 RUN 1 IMG 0647 RUN 1IMG 0651 RUN 2IMG 0649 RUN 3


3.3 Video Clips  

At least 3 best videos are recorded and upload into Youtube.
The 3 links are pasted here and in the Blog.

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