Foot-pounds to miles per hour help

[Adama18]

I have been looking at the Anzio 20mm rifle for work and it is has 22,000 foot-pounds of kinetic energy and I what to know how fast that is in miles per hour

[swansont]

I have been looking at the Anzio 20mm rifle for work and it is has 22,000 foot-pounds of kinetic energy and I what to know how fast that is in miles per hour

 

Kinetic energy is not speed. You need to know the mass of the bullet, and then you can solve KE = 1/2 mv²

[Adama18]

Oh right yeah thanks for that:)

[imatfaal]

I have been looking at the Anzio 20mm rifle for work and it is has 22,000 foot-pounds of kinetic energy and I what to know how fast that is in miles per hour

 

For work? That's a military spec anti-materiel rifle.

 

Convert 22,000 foot pounds to joules - 29,828 joules

Convert 800 grains to kilograms - .0518 grams

 

KE = 1/2 mass * velocity squared

 

velocity = 1072 m/s which is awfully fast

 

Convert 1072 m/s to miles per hour - 2,398 mph. And you need this for work?

[J.C.MacSwell]

 

For work? That's a military spec anti-materiel rifle.

 

Convert 22,000 foot pounds to joules - 29,828 joules

Convert 800 grains to kilograms - .0518 grams

 

KE = 1/2 mass * velocity squared

 

velocity = 1072 m/s which is awfully fast

 

Convert 1072 m/s to miles per hour - 2,398 mph. And you need this for work?

grams should read Kg (which you obviously knew when you calculated) but where did the 800 grains come from to give you the mass? Is that a standard bullet for that rifle, on which the 22,000 foot pounds is based?

[Acme]

For work? That's a military spec anti-materiel rifle.

 

Convert 22,000 foot pounds to joules - 29,828 joules

Convert 800 grains to kilograms - .0518 grams

 

KE = 1/2 mass * velocity squared

 

velocity = 1072 m/s which is awfully fast

 

Convert 1072 m/s to miles per hour - 2,398 mph. And you need this for work?

I'm seeing 1600 to 1700 grains for bullet weight.

US Shooter.com

20×110mm USN @ Wiki

 

1600 grains = 103.6783g = 0.1036783kg

v=758.55m/s = 1,696.82mph So Mach 2.23 for a 1600 grain round compared to Mach 3.15 for a 800 grain bullet. Can you hear me now?

At around $13,000 and ~$15 per round for practice loads, Anzio touts the 20mm rifle as "huge amounts of fun".

Mag-Fed 20MM Rifle

 

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Edited October 7, 2015 by Acme

[imatfaal]

grams should read Kg (which you obviously knew when you calculated) but where did the 800 grains come from to give you the mass? Is that a standard bullet for that rifle, on which the 22,000 foot pounds is based?

 

The wiki page for the gun showed two or three different rounds - one of which was a lighter bullet with the amount of energy listed in the OP

The Anzio 20/50 has approximately 22,000 foot-pounds (29,828 J) of kinetic energy with an 800-grain bullet. It does this by effectively taking the .50 BMG projectile, which already is relatively large and travels extremely fast, and effectively increases the already supersonic bullet to over 1.3 times its normal flight velocity, creating more kinetic energy without the need for a larger and heavier projectile.