FPE general formula?

[ora8i]

In grains (for pellets) its ((fps)*(fps)*(weight grains))/450240

But what is it in pounds?

I tried ((fps)*(fps)*(weight pounds)) but that gave a very big number!!

I’m trying to work out how many FPE a car carries at a given speed.


Thanks All


Ora

[Numb Nut]

Roughly 1 gram = 15.4 grains and 1 mph = 1.47 fps, so a car weighing 1 metric ton doing 30 mph has kinetic energy of (30 * 1.47)^2 * 1000000 * 15.4 / 450240, about 66500 FPE!

[tommy6206]

Hi
Its fps x fps x pellet wieght divided by 450240 this will give ftp energy...

[Numb Nut]

There's 7000 grains per lb, so you could use fps * fps * lb / 64 for the approx ft lbs.

[Paul Hudson]

Isn't this just Newton's Third Law?

Momentum = mass x velocity

Weight of car in pounds times its velocity in feet per second = foot pounds energy...

Paul.

Momentum equals mass times velocity!
Force equals mass times acceleration!
Yank equals mass times jerk!
Tug equals mass times snap!
Snatch equals mass times crackle!
Shake equals mass times pop!

[Numb Nut]

Paul, kinetic energy and momentum aren't the same thing!

[ora8i]

66500

That's the size I was getting and people get all legal on us if a pellet gets an extra 1 FPE.

Ora

[pellet]

But pellets are quite hard to steer around obstacles...

[mikebike]

E = m * v * v /2

W = Energy (J)
m = Mass (kg)
v = Velocity (m/s)

[pellet]

But pellets are quite hard to steer around obstacles...

[robinghewitt]

Originally posted by mikebike
E = m * v * v /2

W = Energy (J)
m = Mass (kg)
v = Velocity (m/s)

Works in Imperial just the same

Energy = foot poundals
Mass = pounds
Velocity = fps

It only gets silly if you insist on using bizarre units like foot pounds and grains

[Numb Nut]

Yup, true Robin - but you have to remember to divide the weight of the projectile by the acceleration due to gravity (approx 32 f/s^2) to give you the mass of the projectile.

[figjam]

just you stick to lying low on fragile roofs mate!

stop showing these boys up!

by the way we are up at the new ground on friday mate due to the hall being closed for the easter

rgds

kenny

p.s. doug says cheers!

[robinghewitt]

Originally posted by Numb Nut
Yup, true Robin - but you have to remember to divide the weight of the projectile by the acceleration due to gravity (approx 32 f/s^2) to give you the mass of the projectile.

I think not

[Numb Nut]

Originally posted by figjam
just you stick to lying low on fragile roofs mate!

Forgot I was afraid of heights until the roof started to wobble! Doh!

by the way we are up at the new ground on friday mate due to the hall being closed for the easter

Thanks for the tip - so will we be shooting or building the new sheltered firing point?