Collisions and Momentum: Bouncing Balls
How much momentum does a baseball struck by a bat have?Copyright Courtesy of Ronald C. Modra/Sports Imagery. http://interactive.wxxi.org/node/56477
As a continuation of the theme of potential and kinetic energy, this lesson introduces the concepts of momentum, elastic and inelastic collisions. Many sports and games, such as baseball and ping-pong, illustrate the ideas of momentum and collisions. Students can use the associated activities to explore these concepts by bouncing assorted balls on different surfaces and calculating the momentum for each ball.
Crunch! That is the sound that you hear when two cars crash into each other. This unnerving sound can be a good thing if it is the sound of a wonderful safety innovation developed by engineers, called the crumple zone. Mechanical engineers consider momentum and collisions when designing vehicles. A crumple zone is designed into motor vehicles to absorb the main impact of the energy being transferred during a crash, so the people inside don't get hurt. Airbags are another engineering safety improvement to protect passengers from the impact of collisions.
After this lesson, students should be able to:
- Calculate the momentum of a moving object.
- Recognize that momentum is proportional to mass and velocity.
- Explain that in a closed system, momentum is conserved in both elastic and inelastic collisions.
- Describe how collisions and momentum play an important role in the design of safe automobiles.