ballistic equations

[jim_w]

Hi all.

Does anyone know the maths behind things like chairgun? I got a bargin on a chrono at the gun shop, (I was the only > 14yo in the shop, so he was nice to me! ) so I've been thinking about ballistics. Given my pellet weight, can I just use newtonian mechanics and conservation of energy to work out the trajectory? Or are there special ballistic equations? Presumably I've got to take account of air resistance and things...

[GaraGun]

Don't you come on here with your fancy mathematics young man

'senough to give an old git heart palputations

Good luck in your quest for knowledge

[jim_w]

Bwahahahh. I can't find a smiley for 'waving A-level physics at you', so I'll just give you this one:

[Rich]

Seeing as air resistance has something like 50 times as much influence as gravity on the pellet's flight it would be a mistake to neglect it that's for sure.

Rich

[jim_w]

Yup. Is this what the 'ballistic coefficient' I've seen is for?

[Numb Nut]

Download and install chairgun 2. The equations used to calculate trajectories are in it's help pages if I remember correctly.

[AndyBlissett]

newtonian mathematics will get you most of the way there, Its only for really high velocities that newtonian methematics begins to break down (einstein et al). Air guns dont have velocities anywhere near in this range (you are looking at velocities above 0.5c really)

However, last time i checked i dont think that air resistance is in this field, and and far as i understand it, the rate of slowdown is a function of the balistic coef (but I dont know the function,altough it will probably be eithe linear or quadratic, with 0 constant, as obviously you wont have air resitance at 0 fps!)

Andy

[jim_w]

Andy: yeah, I seem to remember that air resistance goes with the square of velocity... And that's about all I remember from A-levels! ;-P

numbnut: yeah, I'll slide over to the gf's windows box and see what I can do.