1. Gravity Vehicle
San Diego Regional

2. The Goal
Build a ramp and a vehicle powered solely by its own gravitational potential energy to reach a target as quickly and accurately as possible.

3. Vehicle Parameters Vehicle Mass: <=2.0 kg
No electric or electronic components
Must move as a whole – no tethers, anchors, etc.
Only wheels may touch the track
No size limit for vehicle alone – however, in ready-to-run, vehicle and ramp must be no more than cm x 50.0 cm long x cm high

4. Vehicle Dowel >= 20cm <= 1cm <= 0.5cm ~¼” round wood
within 1.0 cm of floor
at least 20.0 cm above floor
<= 0.5 cm in front of dowel except wheel
>= 20cm
<= 1cm
<= 0.5cm

5. Brakes Distance precision depends on brakes. Common Types: String
Wingnut

6. Ramp Shape: Build frame with the shape you want, attach a thin sheet
Flat - Easy to build
Curved - smoother transition
Build frame with the shape you want, attach a thin sheet
Materials
1/8” MDF
Sheet Metal
Ease transition to floor to reduce error
Don’t let dowel scrape floor

7. Release Mechanism Launch using unsharpened #2 pencil Ideas:
May be a part of release mechanism
May extend beyond dimension limits
Ideas:
Drill hole in Ramp, “hang” Vehicle from pencil. Pull out pencil to release.
Cut hole in Ramp, use some other kind of mechanism.
Place release mechanism at top of Ramp (no holes required).

8. Adding Mass Added mass helps overcome friction
Height of added mass raises vehicle center of mass => higher potential energy

9. Examples

10. Vehicle Distance from Target Additional Parameter(s)
Practice Log
At least 4 parameters
At least 10 runs
Target Distance
Vehicle Distance from Target
Run time
Additional Parameter(s)
FIXED
Target Distance
Vehicle Distance from Target
Run Time
SELECTED
# axle turns
Alignment

11. Track Smooth, level, and hard surface
Start Line
Timed
Target Point
1.00m
9.00 – 12.00m
0.50m Line
8.50m Line
Smooth, level, and hard surface
Lines and points are marked with/on 1” tape
Distance between 9 and 12 meters
Regionals: 0.50 meter increments
State: 0.25 meter increments
Nationals: 0.05 meter increments

12. The Competition 8 minutes to setup for and start 2 runs
No electric tools except calculator
Remove alignment or targeting devices before run
Must not touch/push vehicle or ramp when launching

13. Scoring
The Run Score for each run: 2 pts./cm x Vehicle Distance + 1 pt./sec x Run Time + Penalties
Vehicle Distance is point-to-point
Accuracy emphasized over speed.
Only go as fast as you can brake accurately.

14. Scoring – Issues Failed Run
Vehicle moves but does not pass the 0.50 m Timing Line
Time or Distance not measurable
Not started within 8 minutes
Crosses 0.5 m line, but not 8.5 m line => Time = 60 seconds
Non-Run
If the Vehicle does NOT move, not counted as a Failed Run. May try again
Incomplete Practice Log = 250 point penalty
No Practice Log = 500 point penalty

15. Scoring – Tiers
1: A clean run. No violations 2: Competition violation 3: Construction violation 4: Two failed runs 5: Failure to impound

16. Venue Miramar USD – Not announced
Student Services Lunch Area (tentative)
USD – Not announced

17. Suggestions Build slightly less than maximum size & weight
Practice on different types of floors
Clean the floors
Axle bearings reduce friction
Dowels are the most frequent construction violation
Be careful not to accidentally triggering release

18. Resources Problem Solving / Technology CD Gravity Vehicle Digital DVD
scilympiad.com/san-diego-so/QnAs
scioly.org/forums/viewforum.php?f=315