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Homework Help: Recoiling Cannon Momentum

  1. Jun 9, 2010 #1
    1. The problem statement, all variables and given/known data

    A circus cannon, which has a mass M = 4000 kg, is tilted at q = 45°. When it shoots a projectile at v0 = 40 m/s with respect to the cannon, the cannon recoils along a horizontal track at vcannon = 1.5 m/s with respect to the ground.

    a) At what angle to the horizontal does the projectile move with respect to the ground?
    (The angle is NOT 45°)

    b) What is the mass of the projectile?

    c) The cannon is now lowered to shoot horizontally. It fires the same projectile at the same speed relative to the cannon. With what speed does the cannon now recoil with respect to the ground?

    2. Relevant equations
    p = mv

    3. The attempt at a solution

    I have no idea where to begin to solve for the angle.
  2. jcsd
  3. Jun 9, 2010 #2


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    Homework Helper

    When the projectile leaves the cannon, it has two velocities. Vo at angle 45o and Vcannon in the horizontal direction.

    Resolve Vo into two components, Vocos(45) in the horizontal direction and Vosin(45) in the vertical direction.

    Now find the net horizontal velocity. Then the resultant velocity and the angle of the resultant velocity with the horizontal.
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