Chief Delphi - ball speed rule?

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jax1488

07-02-2006 21:04

ball speed rule?

if u do happen to be able to shoot the 3pt goal and 1 pt goal.. but in order to shoot the 1pt goal, the ball had to be on a spin foward. now when the ball hits the ground of course it will make the ball spin along the ground increasing its speed... is that in violation of the rule? and is it that when the ball gets shot out at normal speed or hits the ground making it go faster.. which is what violates the rule? :ahh:

Biff	07-02-2006 21:16

Re: ball speed rule?

Quote:

Originally Posted by jax1488

The answers I've seen so far would indicate that the speed limit is only as the ball leaves the shooter. Any extra speed, forward movement added speed, spin as you describe it are OK. As always the best bet if you are really worried is to post your question on the official First Q and A.

Jeff Rodriguez

07-02-2006 21:17

Re: ball speed rule?

Quote:

Originally Posted by <S02>

Muzzle Velocity - No ROBOT may throw a ball with an exit velocity of greater than 12 m/s (26.8 mph). As a reference, a ball traveling at this velocity when leaving the ROBOT at an angle of 30º from horizontal with no spin will travel approximately 35 feet. A robot that violates this rule will be considered unsafe per <S01>.

Since the rule says 'exit velocity', it indicates the speed of the ball when it leaves the robot.
My opinion, it would be legal.

EricH

07-02-2006 21:18

Re: ball speed rule?

Quote:

Originally Posted by jax1488

The rule is MUZZLE velocity. If it leaves the robot at 12 m/s, then goes faster after ejection, that's not your problem.

jax1488

07-02-2006 21:25

ball speed rule?

sweet... ok then makin sure :-D

Godzilla!

08-02-2006 11:16

Re: ball speed rule?

Quote:

Originally Posted by jax1488

if u do happen to be able to shoot the 3pt goal and 1 pt goal.. but in order to shoot the 1pt goal, the ball had to be on a spin foward. now when the ball hits the ground of course it will make the ball spin along the ground increasing its speed... is that in violation of the rule? and is it that when the ball gets shot out at normal speed or hits the ground making it go faster.. which is what violates the rule? :ahh:

I believe that you are missing two other pieces of the equation -
1. Gravity - Can't live without it :ahh:
2. Friction - Every time that the ball is in contact with a surface it will slow down proportionally to the coefficient of friction between the ball surface and whatever it touches.

Adding additional momentum to a ball after it has exited the "shooter" without violating the "shooter definition" rules would be kind of difficult at best.
:)

Don Wright

08-02-2006 14:19

Re: ball speed rule?

Quote:

Adding additional momentum to a ball after it has exited the "shooter" without violating the "shooter definition" rules would be kind of difficult at best.

Maybe not.

Take a normal two wheel shooter with the wheels vertical and one wheel above the other. The wheels spin in opposite direction to shoot the ball.

But, if the wheels are spinning in the same direction and have some assistance to keep the ball between them, you could put a LOT of spin on the ball.

Then, just drop the spinning ball on the ground. the "exit velocity" is close to zero. Gravity accelerates it towards the ground and as soon as it hits, the spin will shoot the ball in the direction of the spin.

How much and how fast, I don't know and don't have the time to calculate the inertia of a spinning ball at 5000 rpm or something hitting the ground, with friction, accelerating x ft/sec... But, I bet it would accelerate some...

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