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Homework Help: Projectile Motion: Calculate the speed of the plane

  1. Oct 13, 2009 #1
    1. The problem statement, all variables and given/known data

    A plane, diving at an angle of 53 degrees with the vertical, releases a projectile at an altitude of 730m. The projectile hits the ground 5.0 seconds after being released.

    a.) Calculate the speed of the plane

    b.) Calculate the horizontal distance traveled by the projectile during its flight.

    c.) Calculate the velocity of the projectile just before it strikes the ground. Express the answer in magnitude-direction form.

    2. Relevant equations

    3. The attempt at a solution

    I dont even know where to start with this. How am I able to find the velocity of the plane? I can calculate velocity, position, acceleration, etc all day about the projectile. I have the vectors drawn up but I can't put the pieces together. I really just need a place to start.
  2. jcsd
  3. Oct 13, 2009 #2
    Calculate the time it would take the object to fall from this height, and you will see that if it fell straight down it will be a different time, because it travels a greater distance because it has a forward component (from the plane). From here, you can find the velocity of the plane.
  4. Oct 13, 2009 #3
    The time is already calculated in the problem. It says that it takes the projectile 5 seconds to hit the ground. I do understand it has horizontal and vertical components. Maybe I misunderstood you?
  5. Oct 13, 2009 #4
    You have the time that it took to fall, but it did not fall straight down. How long would it take it to fall straight down?
  6. Oct 13, 2009 #5
    Ok, these are my values. I have that it traveled 968.7m in the x-direction. I have it that it traveled 1213m in the lets say, the hypotenuse (if you draw a vector). I found the velocity to be 242.6 m/s. I am not good at explaining because I don't have symbols. Here are the values I came up with.

    a.) 242.6 m/s
    b.) 968.7 m
    c.) 485.2 m/s
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