Recent content by kpadgett

  1. K

    How to Calculate Javelin Throw Dynamics in Projectile Motion?

    I have been sitting here trying to find which variable to choose, and which equation to try to work with the find t or v. There just seems to be an unknown variable too many in every one. I also wonder about the wording. I just need a hint to get started on this.
  2. K

    How to Calculate Javelin Throw Dynamics in Projectile Motion?

    Homework Statement Jill throws a Javelin by first accelerating it from rest through 85 cm and releasing it from a height of 2.2 m at an angle of 35 degrees and it goes a distance of 62 m. A) What are the values of the vertical and horizontal components of initial velocity? B) Find...
  3. K

    Deriving acceleration from Position vector help

    Wow, it was so simple that I never even thought about it. I don't know how id made it through math 137 and still make that mistake. Thank you very much.
  4. K

    Deriving acceleration from Position vector help

    d/dt (pt) woud be (t)? correct? and d/dt (q(t^2)) would be 2qt? so my vector for velocity is V= (t)i + [(-10m/s^2)t]j? Giving the vector A= [d/dt (t)]i + [d/dt (-10(t)m/s^2)] what I can see: 1)The derivative of t would be 1, as with any lone variable? 2)the derivative of 10(t) is t...
  5. K

    Deriving acceleration from Position vector help

    Ok, I now see here that the derivative of dt^2= 2dt. I'm going to see if this helps me out.
  6. K

    Deriving acceleration from Position vector help

    Wouldn't the derivative of a be 0? So then I can find that V= [(0m)+(t)]i + [(0m)-(t^2)]j So V= (t)i + (-t^2) Deriving V, I get that A= (1)i + (-2t)j ? I see my answer here is wrong as well... I really how no clue what I am doing wrong, and I can't even find deriving V and A from an R...
  7. K

    Deriving acceleration from Position vector help

    Isn't the derivative of 2, 1? I apologize, I thought you left variables in the equation until you were done deriving? As in I would put 2 in for t after I had the equation for acceleration?
  8. K

    Deriving acceleration from Position vector help

    Homework Statement An object has a position given by r-> = [2.0 m + (1.00 m/s)t] i + [3.0m−(5.00 m/s2)t2] j, where all quantities are in SI units. What is the magnitude of the acceleration of the object at time t = 2.00 s? Homework Equations All I am thinking here is that I can find...
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