1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Collisions: Ball with initial velocity is kicked, force of kick?

  1. Nov 26, 2011 #1
    1. The problem statement, all variables and given/known data
    A 10 g ball going at a speed of 5 m/s is kicked, and flies off at an angle of 35° at 25 m/s. What was the force of kick?
    Known:
    m = 0.0010 kg
    vi = 5 m/s
    θ = 35°
    vf = 25 m/s

    2. Relevant equations
    mvi = mvf
    F = ma

    3. The attempt at a solution
    Would this count as an inelastic collision?
    In the x direction:
    .0010g(5m/s) + m(0m/s) = (.0010 kg + m)(25cos35)

    After that, I'm really not sure how to get to the acceleration...
     
  2. jcsd
  3. Nov 26, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This is an impulse-momentum problem, not a momentum conservation problem. (You'll need the time during which the kick was applied.)
     
  4. Nov 27, 2011 #3
    In that case, I might have forgotten a variable, as I don't have the question with me. So if I had the time...

    Impulse is F/t and change in momentum right?

    So then, all I'd have to do is set F/t = p_i - p_f?
     
  5. Nov 27, 2011 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Almost. Impulse is F*t, not F/t.
    Set impulse = Δp. (FYI: Change in something is always final - initial.)
     
  6. Nov 27, 2011 #5
    Oh, right, typo on the change in part, and I really do need to start memorizing my equations. Thanks for your help!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Collisions: Ball with initial velocity is kicked, force of kick?
  1. Kicking ball (Replies: 4)

  2. Kicking a ball (Replies: 1)

Loading...