http://www.ck12.org Chapter 9. Energy
- Assuming the first carts started at the same speed in both demonstrations, explain using momentum why the
inelastic collision ended slower than the elastic collision.
Practice problems for elastic collision:
http://courses.ncssm.edu/aphys/problems/collisions/elascoll.html
Review
Questions
- A 4.00 kg metal cart is sitting at rest on a frictionless ice surface. Another metal cart whose mass is 1.00 kg
is fired at the cart and strikes it in a one-dimensional elastic collision. If the original velocity of the second
cart was 2.00 m/s, what are the velocities of the two carts after the collision? - Identify the following collisions as most likely elastic or most likely inelastic.
(a) A ball of modeling clay dropped on the floor.
(b) A fender-bender automobile collision.
(c) A golf ball landing on the green.
(d) Two billiard balls colliding on a billiard table.
(e) A collision between two ball bearings.
- elastic collision:One in which both momentum and kinetic energy are conserved.
Regardless of what events occur, in all closed systems, energy will be conserved. Most of what we think of as
“energy” is in fact kinetic energy, or the energy of motion. Energy that is stored for later use is called potential
energy. In elastic collisions, momentum and kinetic energy are conserved; in these cases, it is possible to calculate
the colliding objects’ initial and final velocities using the conservation of momentum and conservation of kinetic
energy equations.