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Homework Help: Cannon recoil speed

  1. Mar 2, 2004 #1
    I have doubt about my answer to the following question:

    A cannon is rigidly attached to a carriage which can move horizontally without friction. The cannon fires a 88 kg projectile at a velocity of 161 m/s directed 40.2 deg. above the horizontal. If the mass of the cannon and carriage is 4371.25 kg, find the recoil velocity of the cannon.

    I used m1v1 = m2v2 to solve.

    88 * cos40.2 * 161 = 4371.25 * V

    V = 2.4756 m/s, the answer was wrong,. then I tried to assume the projectile's speed is relative to the cannon,

    88*(161*cos40.2 - V) = 4371.25 * V

    V = 2.42674 m/s, still wrong. Can you help me, thanks
  2. jcsd
  3. Mar 2, 2004 #2
    I got it thanks

    The sign was wrong. I simply put minus in front of my first answer. Thanks anyway.
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