The moment the nock leaves the string.

 

Correct.

 

I set my chrono 3 ft away. Always wanted to set it at 20 yrds to see what arrow is doing and it's KE at that range but not risking my shot.

 

Why not? The screen is pretty large at 20 yards. I used to shoot mine out to 50 yards so I could compute KE. And NO, I never shot it.

 

Very good question! What it matters I don't know. I would guess as soon as the oscillations cease.

 

As soon as the arrow leaves the string there is no longer a outside force acting upon it to accelerate it (except for gravity but it's not accelerating its not in the same direction so it has no effect on the velocity of the arrow) anyways without a outside force acting upon it begins to decelerate immediately due to friction caused by the air. And yes I am in physics right now

 

Well actually in my post above I left something out, it is accelerating still but in the opposite direction so that causes it to slow down. That is called accelerating negatively, I have a love hate relationship with physics some of it is interesting and I can apply if something like this but other parts bore me to tears.

 

The moment the string stops pushing begins to gradually slow down.

 

It depends on the make and model and cam timing. True story.

 

Explain that please.

 

The second it leaves the string!

 

As soon as the arrow nock leaves the strings.

 

Where u studying wbxl?

 

Well actually still in high school, I'm from tuscaloosa just I'm in ap physics at the moment so of all the questions I've seen so far on here this one was definitely up my alley.

 

So would the true answer be (using those theories), that nano second just before the nock turns loose? I say that because of the little bit of friction between the nock and string would also slow it and the bow has done its job.

 

A nano second before the nock leaves the string.

 

10-4

 

I don't think it's the moment the nock leaves the string. The string only gains speed until the limbs are back at brace. From that point, it's losing speed. If the string travels 2" forwards of where it sits at brace, it's actually losing speed and causing the arrow to slow down. IMO, the fastest the arrow will ever be going is exactly at the point where the string reaches the bows brace height and not when the arrow leaves the string.

 

^^^^^^^^^^^^We have a winner. Well, unless you are shooting at a down angle. Then it is dependent mostly on fletching size and how far down your arrow will go before it hits the ground. It will accelerate until it hits terminal velocity.

 

You know, it's real simple. Shoot the 1 arrow length back from the face of the chronograph. Establish average speed. Step back two feet and shoot again. I've seen velocity drop doing just this. It's no different with firearms, out of the barrel the bullet starts losing velocity. Had my first chronograph back in....1975 or 1976, screen type, and in ??? went with the Shooting Chrony. I've had one ever since....

 

Since the arrow is no longer accelerating after it leaves the string it must be slowing down-so it is at it's fastest at the instant it leaves the string.
Maybe it is fastest while still on the string when the bow is still at peak weight on it's way to brace??????

 

man I am grinning from ear to ear. I like this forum. so what you are saying is if were a pitch throwing a fast ball it is at its fastest as he releases it?

 

sorry can't look at the screen and type at the same time. laughs

 

it's the fastest during the time the cams are in their peak thrust period of rotation. that is before the arrow leaves the string. the act of leaving the string actually uses up some velocity.
if the question is, "when is the arrow at it's highest velocity, during flight"....then yes, just after it leaves the string.