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Homework Help: Flying car

  1. Jan 16, 2005 #1
    .............| 1.48 meters high
    ________|_______________________(must land here)

    .............|------21.1 meters--------|

    A stunt driver wants to make his car jump over a distance of 21.1 meters below a horizontal ramp

    With what minimum speed must he drive off the horizontal ramp? The vertical height of the ramp is h = 1.48 m above the ground and the horizontal distance he must clear is d = 21.1 m.

    What is the new minimum speed if the ramp is now tilted upward, so that "takeoff angle" is 11.6° above the horizontal, and nothing else has changed.

    Can someone please give me some tips on how to start on these 2 problems?

    Thank you very much for your help
    Last edited: Jan 16, 2005
  2. jcsd
  3. Jan 16, 2005 #2


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    Yes,u can start by applying the laws of kinematics of movement with (presumably) constant acceleration in free fall.

    Post some ides,equations...

  4. Jan 16, 2005 #3
    Here is what i have so far

    Initial Distance Xo = 0 m
    Final Distance X = 21.1 m
    Acceleration = 0 m/s^2

    Initial Height Yo = 1.48m
    Final Height Y = 0 m
    Acceleration = -9.8 m/s^2

    I have tried applying the informaiton above to the position function and velocity functions however I end up with 2 unknown variables time and the initial velocity of distance and height


    X = (1/2)(0)(t^2) + Vo(t) + 0
    X = Vo(t)


    Y = (1/2)(-9.8)(t^2) + Vo(t) + 1.48

    Y = (-9.8)t + Vo
    Last edited: Jan 16, 2005
  5. Jan 16, 2005 #4


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    Now come u got 3 equations,two of which for "Y"??The last one is completely wrong...

  6. Jan 16, 2005 #5
    I have found my mistake. The initial velocity of height is 0m/s. If i just used the position function and plug all the values above in, then i will have found out the time for the car to land would be .5496 seconds. Then plug the time and the rest of the values for Distance, i would find the inital velocity of distance = 35.6985 m/s
  7. Jan 17, 2005 #6


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    I didn't check the numbers,but i'm hoping u knew how to do them.
    Okay,what about the second part??
    Think about like that:With what velocity do i need to throw a stone at an angle of 11° to the horizontal,if i am at a height (above the ground) of 1.48m and the stone must land 21.1 meters away,measured on the "x" axis?

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