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Homework Help: Missle Defense System (Projectile Motion)

  1. Jun 29, 2016 #1
    You are designing a missile defense system that will shoot down incoming missiles that pass over a perimeter defense post. The set-up is shown below. An incoming missile passes directly above the defense base. Radar at the base can measure the height, h, and speed, v1, of the incoming missile. Your Patriot Rocket is set to fire at an angle of θ = 62.0 degrees from vertical. You design the Patriot Rocket so the magnitude of its acceleration is given by:

    a = A(e^−bt)

    where A can be set on your Patriot Rocket as it is fired, and b = 0.15 s-1. The direction of your Patriot Rocket's vector acceleration stays at the same angle, θ, for the entire trip. If an incoming missile passes over the defense base at a height of 4.50 km and at a constant speed of 799.0 m/s (this means that v1 is constant), solve for the value of A your Patriot Rocket must have in order to hit the incoming missile. You will also need to enter results from intermediate steps of your calculation, including the time ∆t in between launch and impact, and the horizontal distance ∆x from the launch station to the impact position.

    2. Relevant equations

    3. The attempt at a solution
    I'm stuck at even where to begin. I was thinking of taking the integral of the acceleration but I still am left with 2 unknowns in 1 equation.

    Attached Files:

  2. jcsd
  3. Jun 30, 2016 #2


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    Gold Member

    There are two dimensions, so two equations. Please post your working as far as you get.
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