Speed versus momentum

[madeinuk]

[archer36]

Well I never saw that one to demonstrate momentum but it explains it. 

[hunterbob1]

Who said White Men can't jump.

[not on the rug]

Momentum is everything.

[MGHunter66]

3 minutes ago, not on the rug said:

Momentum is everything.

That’s what she said 😀

[Integracingsr]

Finally, an example that makes sense to me! 

[archer36]

Obviously they work together. More speed gives you more momentum with identical weight. A 500 gr arrow has more momentum when shot out of a 400 fps bow compared to a 250 fps bow. 

Edited August 26, 2021 by archer36

[Greybeard]

Hole would have been bigger with rage.

[JHbowhunter]

who can calculate the Kinetic Energy of the example shown above?

 

kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared.

 

I will guess - 

360 lbs, so (180 * 8 mph (squared) ) so wouldn't that be a KE of  180 * 64 = 11,520 

But I digress - as a 360 grain arrow at 300 fps has KE of 71.93 foot lbs. Using this calculator

https://www.realtree.com/kinetic-energy-and-momentum-calculator

Unfortunately the calculator has limit of 750 grains

 

But I found a better KE calculator that has it come out to 770 ft lbs of KE.   So my self-calculation was way off.

Use this calculator for all your KE needs

 

https://www.omnicalculator.com/physics/kinetic-energy

 

BTW - This does NOT make me a bigger nerd than @Haskell_Hunter

[Haskell_Hunter]

4 minutes ago, JHbowhunter said:

who can calculate the Kinetic Energy of the example shown above?

 

kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared.

 

I will guess - 

360 lbs, so (180 * 8 mph (squared) ) so wouldn't that be a KE of  180 * 64 = 11,520 

But I digress - as a 360 grain arrow at 300 fps has KE of 71.93 foot lbs. Using this calculator

https://www.realtree.com/kinetic-energy-and-momentum-calculator

Unfortunately the calculator has limit of 750 grains

 

But I found a better KE calculator that has it come out to 770 ft lbs of KE.   So my self-calculation was way off.

Use this calculator for all your KE needs

 

https://www.omnicalculator.com/physics/kinetic-energy

 

BTW - This does NOT make me a bigger nerd than @Haskell_Hunter

You actually think that guy was running faster than 2MPH?  I question your assumptions.

Yes, I am the bigger nerd, hands down!

[not on the rug]

2 hours ago, archer36 said:

Obviously they work together. More speed gives you more momentum with identical weight. A 500 gr arrow has more momentum when shot out of a 400 fps bow compared to a 250 fps bow. 

Correct.  Also, a bow  more efficiently transfers energy to a heavier arrow, and regardless of the bow speed, the heavier arrow maintains a higher percentage of that momentum downrange than a lighter arrow

[hammer4reel]

3 minutes ago, not on the rug said:

Correct.  Also, a bow  more efficiently transfers energy to a heavier arrow, and regardless of the bow speed, the heavier arrow maintains a higher percentage of that momentum downrange than a lighter arrow

That same arrow wastes twice as much energy into the 10” of ground on the offside of the deer .

too many guys way over think the heavy arrow .

it’s an arrow, not a lawn dart 

[BCsaw]

You still have lawn darts? :-)

Sent from my SM-N975U using Tapatalk

[not on the rug]

14 minutes ago, hammer4reel said:

That same arrow wastes twice as much energy into the 10” of ground on the offside of the deer .

too many guys way over think the heavy arrow .

it’s an arrow, not a lawn dart 

Too many guys think in absolutes.  You don't need a 350g arrow...but you don't need a 700g arrow either.  Plenty of middle ground in there for most big game hunters. 

Also, energy isn't "wasted" if it blows through a deer.  The arrow did it's job.  Saying the energy is wasted is silly.  

Build a "plan B" arrow...one that will do it's job in case you miss the mark

Edited August 26, 2021 by not on the rug

[Haskell_Hunter]

1 minute ago, not on the rug said:

Too many guys think in absolutes.  You don't need a 350g arrow...but you don't need a 700g arrow either.  Plenty of middle ground in there for most big game hunters. 

This is why I shoot them with a gun.  Or a crossbow.  I don't have to think about it, I just have to aim and pull the trigger.

Now, if we're takin' about rage versus fixed broad heads, I have both that I will be testing out with my crossgun this year.