How will FIRST measure muzzle velocity?

I was reading inthe rules that there was a max speed of the balls. I think its a great rule because everybody is on the same level when it comes to how fast a ball can travel. Rules are also great if you can police them, how does FIRST plan to police this rule, are they going to have six different radar guns to clock how fast the balls are going? I hope they have a simple way to inforce this rule or I see another “what is entanglemant?” debate we had a couple of years ago.

It’s a safety and inspection kind of rule. You’ll just have to satisfy the inspectors that your robot isn’t going to throw balls faster than 12 m/s. That should be good for the whole competition unless you start throwing balls across the entire field or denting the plexiglass or something.

I think the inspection that the robot goes through before you can compete will probably include a speed test of your robots throwing speed. And if the judges or an official thinks that you changed your launcher they will make you test it again. thats the most logical thing i can think of since i dont think each ref will have a radar gun. :slight_smile:

If FIRST believes there will be an issue with exceeding the rule for “muzzle” velocity of a ball being airborne, it would be very easy for them to set-up a test of some kind at the SAME time & place that they’ll be checking your robot for weight and size constraints.

Basically, a robot MUST get to mid-field or “closer” in order to NOT be in violation of the high-speed, long-toss rule. Maybe they’ll set-up a test station across the top of the pits (wow…)

Hopefully, with the official Poof-branded balls, it won;t be a big problem across the board, but wait and see during the build season who starts to “tout” their hypersonic ball tosser first…LOL :yikes:

knocking holes through the ceiling of the arena with a nerf ball would be a dead give-away :^)

or a switch on the operator interface for the launcher, with two settings:



I fear any team that can get a ball to the ceiling at Reliant Arena. And if a team hits the ceiling in the Georgia Dome? That’d be quite a feat. (No fair smuggling a robot into the nosebleed seats.)

I don’t know if they’ll need to measure it, as they already know the max distance possible (which is for the “best” angle, which I believe to be around 30 degrees, at the max muzzle velocity they’ve specified).

So, if your scoring from further out than that, you’ve got a lot of explaining to do.

  • Scott 358

tail wind?

positive spin (floater pitch)?

Human player telekinesis?

spacial disturbance in the time/space continuum?

Heh heh. Check out the special “black box” we will have on our robot. Just don’t stand too close. We lose way too many rookie team members that way… :slight_smile:


Yeah - only the head ref gets the radar gun!

Am I missing soemthing? The physics I remember says that the “best angle” is 45°. :confused:

45° gives you the farthest distance with no air (wind) resistance.

With something big and light (like a nerf ball) the best angle will be different (air resistance has a greater effect on the trajectory than gravity does).

The “best angle” still appears to be near 45 degrees. I’ve made up a spreadsheet that roughly accounts for air resistance and I’m still getting the best range at around 43 degrees. Definitely not 30 degrees. However, my spreadsheet also doesn’t think 35 feet is possible at 30 degrees, so make of that what you will. This is, of course, completely theoretical. We’re going to cobble together a prototype in a day or two and see what that says.

A quick prototype that we created had one of the balls going well over 40 feet at a speed of approx 24 mph, and that was measured with a radar gun that targeted the ball as soon as it left the muzzle.

I concur with Jon, we built a quicky prototype last night - but I didn’t have gun to measure the speed.
My prototype was set at 30 degrees, after firing the ball it landed well beyond 35 feet, so I had to back off on the force being used in order to stay within the 12 m/s rule.

No doubt exceeding the 12 m/s can easily be accomplished - hand held radar guns could be used to measure with if available, other wise during inspection each team could be asked to set up at the 30 degree angle and shoot a ball to see if the travel is in excess of 35 feet.

The question is now like last year with seeing how many tetras a team could raise or how much weight it could lift. What speed can you get your Poof balls to go upon exiting the muzzle?

geez how big of wheels and motor r u using to get the ball to go that fast we still are trying to figure it out.

Who said anything about a motor? There are many other methods available and easy to prototype.

wow! did you use a differential equation for the air resistance in the spread sheet? I’m lucky if I can set up Excel to sum a column of numbers and get the right results!

Like most things in the real world projectile motion in air is nonlinear. Even with differential equations the best we can do is approximate it.

…robot moving forward at… Gee, the robot speed isn’t limited*!! Add a few meters per second to that velocity.

*By rules. Physics is another matter.