Crave The Wave

Simple Machines

2014-10-27 20:39 For the first class lever component, does the total length of the bar have to be less than 80 cm or the individual sides from the fulcrum?

For the class 1 lever the load point to effort point measurements must be less than or equal to 80.0 cm. The size of the the fulcrum is irrelevant to this measurement.

2015-02-13 20:13 How many significant figures or decimal spots should the ratios be rounded to?

Mass ratio answers should be entered to the number of significant digits allowed by the Event Supervisor.

2015-02-13 20:26 Does the ratio have to be simplified to a decimal value or are you allowed to leave it as a fractional value?

The ratio should be presented as a decimal value, unless otherwise authorized by the Event Supervisor.

2015-05-07 10:55 Must each mass fit inside the 15 x 15 x 20 cm box independently, or do all three masses have to fit within this box simultaneously? Will the dimensions of the masses for nationals be announced prior to the tournament?

Each mass must fit within the box individually. The dimensions are not required to be announced prior to the competition.

2015-02-15 17:30 For simple machine, device portion of competition, when asking for the ratio, what format do the judges want the answer in, decimal, or fraction? I.e. "1:3" or "0.33" ?

The way the ratio is recorded will be up to the local event supervisor.

Air Trajectory

2014-10-25 21:17 Please define "plastic practice golf balls". Are high density polyurethane foam practice golf balls allowed?

The most common type of plastic golf balls are plastic dimpled and plastic with holes and HDPE foam types are legal. As long as they are commercially marketed as "plastic practice golf balls", they may be used. It is recommended that students bring the packaging if there is a question.

2014-10-25 21:32 Its stated that the launch area is "1.00 m x 1.50 m (parallel to the launch direction)," does this mean that launch area is 1.50 m in length along the launch access and 1 m wide?

Yes, the 1.5 m side of the launch area is the side that is parallel to the launch direction and the front of the launch area is 1 m wide.

2014-10-25 21:45 The height of the target is not specified in the rules. What are the limits on how high or how low the targets can be compared to the launching area?

Rule 4.d. explicitly says that the target is either tape on the floor or panels lying on the floor. There should not be any significant difference between the floor height in the launch area and the targets.

2014-10-25 21:59 Can a team take one shot each for both targets and then decide which target it takes a second shot and/or take a bucket shot (if allowed by 4.i)?

Competitors may choose either target for their first shot. They may then choose to take their second shot at the same target or their first shot at the other target. If they qualify to take a bucket shot after their first shot at a particular target, they must ask for the bucket when they wish to take the second shot at that target.

2014-10-25 22:05 How can the competitors make measurements after the launch without touching the target?

Competitors will be told the distance of the targets from the launch area and can measure their impact locations from the launch area if outside of the target.

2014-10-25 22:11 If the projectile bounces off the bottom of the bucket and then out of the bucket would the bonus count?

Rule 4.i states that "making contact with the inside bottom surface is worth an additional 100 points." It does not state that after making contact the projectile must remain in the bucket, so the bonus is given even if the projectile subsequently bounces out of the bucket.

2014-10-30 17:49 Is a Foose ball legal to use as a projectile?

No, only the listed items in rule 3.f. are allowed as projectiles.

2014-11-25 19:58 Does the gravitational potential energy need to convert directly into air pressure or can it go through multiple conversions to get to the air pressure force.

It can go through multiple conversions, but 100% of the energy must initially be gravitational potential energy.

2014-11-25 20:03 Does the air pressure/movement generated by by the falling mass have to be immediatley applied (either directly or indirectly) to the projectile or can it be stored and then released?

It can be stored and released, but 100% of the initial energy must come from the falling mass and event supervisors must be able to verify this. Also, all chambers must automatically return to ambient air pressure.

2014-11-25 20:12 During competition, can a team use a different air chamber for each launch?

Yes, as long as the device remains safe and within other specs.

2014-11-25 20:28 Polyurethane foam practice golf balls almost never use the word "plastic" in their advertising, although polyurethane is clearly a plastic. If the package says "PU foam practice golf balls" is it OK?

All the words "plastic", "practice", "golf", and "ball" must appear somewhere on the packaging or advertising description of the product, but not necessarily all in the same spot.

2015-01-05 22:09 The kids want to know if they are restricted to only these balls, or can they used other soft commercially-produced balls?

Teams must use only the type of balls listed with in rule 3.f.

2015-01-27 20:13 Are teams of the same school able to share their falling masses.

This is up to local event supervisors.

2015-01-27 20:20 Will these bucket distances be subject to the interval limitations stated in section 4e (e.g. 1.00 m increments for regionals)? Or could the bucket distance be at arbitrary distances (e.g. “4.6 m from the launch line and 1.35 m to the right.”)...

Bucket distances can be arbitrary intervals.

2015-02-11 20:07 Can teams impound multiple masses and use different masses for each launch given the masses are less than the maximum mass allowed?

Per 3.a. more than one mass may be impounded, but the total sum of all masses must be less than 3.5kg (Div C), 5.0kg (Div B)

2015-02-11 20:12 Can multiple triggers be used (ie one to release the falling mass and then one to release stored pressure)?

Yes, if the system is designed in such a way that were the second trigger not activated, other relevant rules are still met, such as rule 3.c regarding automatically returning to ambient air pressure and 4.c automatically returning to the launch area.

2015-02-11 20:15 Is a laser permitted for use as solely as an aiming device?

Yes, as long as it is a removable tool that is not part of the device and removed prior to launch. The official SO laser policy must also be followed:

2015-03-06 11:47 After the launch, is it permissible to blow in the tube to re-inflate (uncrush) the bottle to get ready for the next launch, as long as, before the launch the bottle is at ambient pressure?

Yes. Competitors are permitted to force air back into the pressure chamber to return it to its initial shape and volume. The chamber must still be at ambient pressure at launch.

2015-03-17 10:49 Can I use a level app on my phone do determine the pitch of the barrel if it is removed after use? It will also only be used for aiming.

No. General Rule #2 prohibits devices such as cell phone during the competition.