3.1 Trial Test and Design Modification
3.1.1 Trial Result Table
Run Number
|
Run 1
|
Run 2
|
Run 3
|
Total time of Run/s
|
7
|
6
|
6
|
Total distance of Run/m
|
7
|
6.5
|
Unknown (off-course)
|
Time for lever to fully release/s
|
3
|
3
|
3
|
Distance car travels while lever is releasing/m
|
3
|
3
|
2.5
|
Observations – did car travel smoothly,
|
Yes
|
Yes
|
Yes
|
Orientation
|
It travelled at a slightly inclined angle to the right
|
It travelled mostly straight
|
It swerved to the right and headed in a direction perpendicular to the track.
|
Did lever / string operate smoothly?
|
Yes
|
Yes
|
Yes
|
Filename of video recorded is:
|
NIL
|
NIL
| |
Area for improvement (1 only)
|
The drive wheels are not driving the car efficiently.
|
The striker mechanism of the mousetrap does not wind forward completely, reducing wheel rotations.
|
Wheels and axle are not aligned properly, causing it to swerve out of the track.
|
Possible reason (1 only)
|
Lack of friction on wheels
|
The lever extension hits the bait pedal, preventing the mechanism from winding forward fully.
|
Wheels were not secured perpendicular to the axle, thus the misalignment caused the car to travel in the wrong direction.
|
Modification made (1 only)
|
Added tape to the CD wheels to add more friction as the CD wheels.
|
Lever was shifted to the right.
|
Wheels were re-glued perpendicular to axle.
|
3.1.2 Modification Procedures
- Shift of Lever
- Lever was shifted to the right of the car to allow the striker mechanism of the mousetrap to wind forward completely and avoid hitting the bait pedal. This allows a greater number of wheel rotations due to the power stroke.
- Increased Wheel Traction
- Masking tape was added to the drive wheels to increase friction acting on the wheels, such that it has better traction.
- Extension of lever
- The lever was replaced with one of longer length. Extension of the lever allow the power stroke to be increased, furthering the distance the car can travel.
- Straightened and reinforced wheels
- Straightening of the back wheels was done by re-gluing the wheels onto the axle. This fixes the problem where the car, due to the (unintended) inclination of the wheels travels off course when on the track.
- Reinforced back frame
- Glue was added over the rear frame which holds the eye-hooks connected to the axle. This prevents the frame from tearing due to the stress caused by the retraction of the metal striker of the mousetrap.
- Shifted egg container to main body
- Prior to modification, the egg container was held by bluetack at the front of the car. It has since been shifted to the main body, where it is more stable and less prone to fall off.
3.2 Test Data
3.2.1 Measurement Data Table (After Modification)
Mass of your car
|
425g
|
Mass of each wheel (or one of they are all the same)
|
15g Rear, 25g Front
|
Wheel diameter
|
12cm Rear, 4.7cm Front
|
Axle diameter
|
5mm
|
Length of string (power stroke)
|
32cm
|
Approx. number of wraps of string
|
20
|
Length of lever extension
|
20cm
|
Overall length
|
36cm
|
Overall width
|
9cm
|
Overall height
|
12cm
|
3.2.2 Trial Result Table (After Modification)
Run Number
|
1
|
2
|
3
|
Total time of Run/ s
|
3.4
|
4.7
|
1
|
Total distance of Run/ m
|
5.5
|
4.6
|
0.2m
|
Time for lever to fully release/ s
|
2.5
|
3.2
|
NIL
|
Distance car travels while lever is releasing/ m
|
3
|
5
|
NIL
|
Observations – did car travel smoothly,
|
Yes
|
Yes
|
No. (Car disintegrated)
|
straight, always forward, etc?
|
Yes
|
Yes
|
NIL
|
Did lever / string operate smoothly?
|
Yes
|
Yes
|
NIL
|
Filename of video recorded is:
|
3.3 Video Clips
- Pre-Modification No.2
- Post-Modification No.1
- Post-Modification No.2
-
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