1. Not finding help here? Sign up for a free 30min 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!

A 3.0 g coin moving to the right at 26.0 cm/s makes an elastic head-on colli

  1. Dec 11, 2007 #1
    1. The problem statement, all variables and given/known data

    A 3.0 g coin moving to the right at 26.0 cm/s makes an elastic head-on collision with a 12.0 g coin that is initially at rest. After the collision, the 3.0 g coin moves to the left at 12.5 cm/s.
    (a) Find the final velocity of the other coin.
    _____cm/s to the right
    (b) Find the amount of kinetic energy transferred to the 12.0 g coin.
    _____Joules

    2. Relevant equations

    for part a, i know you have to do conversions to get to M and Kg.
    for part b, .5mv^2

    3. The attempt at a solution

    i know that KE of the 2nd coin = (m of second coin)(.5)(Velocity of second coin ^2)

    but i'm STUCK on part A!!!!
     
  2. jcsd
  3. Dec 11, 2007 #2
    Use conservation of momentum:

    p(initial)=p(final)

    p=m*v
     
  4. Dec 13, 2007 #3
    i found part A, and it's 9.6cm to the right.
    but now i am stuck on part B.
    no matter what i do, it's not working!

    .....i tried this:
    KE of second coin=(Mass of second coin).5(Velocity of 2nd coin^2)
    so it'd look like:
    (.12)(.5)(9.6^2)
    BUT since it's 9.6 CM/s, to convert it to m/s it would be .096
    (.12)(.5)(.096^2)
    which is: .00055296


    why is it wrong!?
     
    Last edited: Dec 13, 2007
  5. Dec 13, 2007 #4
    What's the answer given in the book? Btw, 12.0 g is 0.012 kg.
     
  6. Dec 13, 2007 #5

    cristo

    User Avatar
    Staff Emeritus
    Science Advisor

    I'll unmark this as solved since you still seem to be asking questions on it.
     
  7. Dec 13, 2007 #6
    ok i think this is how u do it
    first u need to find kinetic energy before contact and find the kinetic energy of the coin A
    and u subtract the original kinetic to the kinetic of coin A u will get the kinetic of coin B
    (assumed that the moving coin is A and the resting coin is B)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: A 3.0 g coin moving to the right at 26.0 cm/s makes an elastic head-on colli
Loading...