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Homework Help: Car Collision. Please Help

  1. Oct 21, 2007 #1
    Car Collision. Please Help ASAP!!!!!!!!!!!!!!!

    Sistuation: There is a right angle collision with a truck and a car. The front of the car collides with the side of the truck. I am given these numbers. The truck has a 5 cm dent, and the car collapsed a total of 100 cm. I know the mass of the truck and the car. I am given the driver injuries. There is a bruise on her head, and she suffered from major neck and belt laceration. The doctor said that these injuries can only result from an impact ranging between 20 through 25 g. My goal is to figure out the velocity of the car before impact.

    So far: I know conservation of momentum comes into play. I think Delta V as comes into play but I am having a difficult time calculating this since it is broken up in components. I need some help starting this problem. Could energy equivalent Speed, delta v, barrier equivalent velocity or any of those help me. HELPPPPPPPPPPPPPPP QUICKKKKKKKKKKKKKk.
  2. jcsd
  3. Oct 22, 2007 #2
    This is basically a kinematics problem rather than a collision one. Let the velocity of car before collision be u. Final velocity is zero. Acceleration (retardation) is 20g = -196 m/s^2 (min) and 25g = -245 m/s^2 (max). Displacement = Dent in the truck + collapse in the car = 105 cm = 1.05 m. Apply appropriate kinematic equation to determine u (max) and u (min).
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