1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Finding muzzle velocity using range and height of barrel

  1. Jun 13, 2010 #1
    1. The problem statement, all variables and given/known data
    Ok, so pretty much, I built an air cannon for my physics assignment. I need to determine the muzzle velocity. I know the angle of the barrel, the height of the muzzle about the ground and the distance the projectile covered. I fired projectile at multiple pressures in order to determine the effect of pressure of muzzle velocity. I am ignoring drag and friction for these equations.

    2. Relevant equations
    Let v0 = Initial muzzle velocity
    o = angle of barrel = (33.82 Degrees if this is neccessarY)
    Height of barrel = h = 1.13m

    3. The attempt at a solution
    Total time of flight= t = v0sin(o)/9.8^2+ (v0sin(o)^2/9.8^2 - 2*h/9.8)^0.5
    Distance travelled = v0cos(o) * t
    = v0cos(o) * (v0sin(o)/9.8^2+ (v0sin(o)^2/9.8^2 - 2*h/9.8)^0.5)
    I need the rearrange this equation so v0 is the subject so I can implement this in an excel spreadsheet as I have literally hundreds of these to determine.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 14, 2010 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    What is your question?

    If you are trying to find muzzle velocity, you have to solve these equations for time:

    (1) [tex]x = v_0\cos\theta t[/tex]

    (2) [tex]y = v_0\sin\theta t - \frac{1}{2}gt^2[/tex]

    Find the muzzle velocity by substituting t into (1).

    AM
     
    Last edited: Jun 14, 2010
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook