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!

Homework Help: Collision question

  1. May 17, 2009 #1
    1. The problem statement, all variables and given/known data
    hi guys,, got a question about collision + rotation ,, the following question is :
    A steel ball of mass 0.5 kg is attached to a cord that is fixed at the other end. The ball
    is then released when the cord is horizontal, as shown in the figure. At the bottom of its
    path, the ball elastically strikes a 2 kg steel block initially at rest on a frictionless
    horizontal surface. The ball is in contact with the block for 2 ms, and the force due to the
    elastic collision is given by:
    F(t) = 8×106t – 2×109t^2
    for 0 ≤ t ≤ 4 ms, where t is the time in seconds. Both the ball and block are considered as
    point particles.

    a) the impulse on the block due to the collision.
    b) the average force of the block from the ball during the period of contact.
    c) the maximum force on the block during the period of contact.
    d) the speed of block immediately after the collision and the length of the cord.

    2. Relevant equations

    3. The attempt at a solution
    i know that J=Favg delta(T) but i dont know either of them and i don't know how to answer the first question ,, i need a way to answer it please so i can continue solving the others

    Attached Files:

    • Q.JPG
      File size:
      54.6 KB
  2. jcsd
  3. May 17, 2009 #2
    I'f I'm not wrong You should integrate the force equation, aka calculate the area under the Graph in bounds 2,0 also convert to seconds.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook