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: Bounce of football (kinetic and potential energy)

  1. Nov 7, 2009 #1
    1. The problem statement, all variables and given/known data

    A football (european) that hits ortogonally a surface will reflect such that the kinetic energy of the ball after the collision will be a fraction of the kinetic energy of the ball before the collision. The football makes a free fall from 50 cm to a floor and jumps to the height of 40 cm. After that the football is kicked into a wall (of the same material as the floor) from 5 meters. The ball hits the wall ortogonally and lands on the floor in the distance a from the wall. Find a.

    2. Relevant equations

    We assume that 4/5 of the football's energy is conserved in a collision because

    U1 = 4/5*U2
    where U1 is the potential energy before the collision, U2 after.

    3. The attempt at a solution

    The ball will have 4/5 of its energy conserved after the collision with the wall. This will make the ball go 4/5 the distance it was shot from, making it reach 4 m.

    This might be right, but we suspect it's too easy. The fact the Ekin energi has v2 makes me suspect our current suggestion is wrong. a might also depend on how hard the ball is shot, but the excercise doesn't state any force that makes the ball go to and collide with the wall.

    Thanks a lot!! :-)
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted