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Finding the angle of projection and its speed in 2D Kinetics

  1. Jul 28, 2015 #1
    1. The problem statement, all variables and given/known data: The trajectory of a projectile in a vertical plane is y = √3 x - (1/5)x2, where x and y are respectively horizontal and vertical distances of the projectile from the point of projection. Find the angle of projection and speed of projection.

    2. Relevant equations: 2-Dimensional Equations and maybe calculus.

    3. The attempt at a solution: Honestly, I can't even understand that how do I begin with this question. I've tried some wild attempts but they landed me no where :-( Can you please guide me with the solution to this question?
  2. jcsd
  3. Jul 28, 2015 #2
    Please post these attempts .

    However I still give a hint :

    What does dy/dx represent ?
    What is the formula for Range ?
  4. Jul 28, 2015 #3


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    Homework Helper

    The angle of projection can be found from the gradient of the graph at what point?
  5. Jul 28, 2015 #4
    I figured out the formula for Ran
    I figured out the formula of range as: u2Sin2(theta)/g

    Can you tell me that how would it be done further?
  6. Jul 28, 2015 #5
    Sorry to ask a stupid question but what do you mean by point? Can you please show me how would it be solved?
  7. Jul 28, 2015 #6
    Here - dy/dx at x = 0 represents tan(θ) ( where θ is angle of projection ) .

    Find range , and then using formula for range find u .
    Last edited: Jul 28, 2015
  8. Jul 28, 2015 #7


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    Homework Helper

    What does the trajectory or path of the projectile look like?
    What is the equation which describes the path or trajectory?
  9. Jul 28, 2015 #8


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    Staff: Mentor

    Please attach your working for this.
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