The Bowling Ball Pendulum
By pulling the bowling ball back a given distance and simply releasing it from rest; you are able to demonstrate one of the most fundamental concepts in physics. The conservation of energy is a topic that permeates every aspect of the physical world and the bowling ball pendulum shows how even the slightest miscalculation could result in horrible results.
- Watch Paul Hewitt demonstrate how it is done at the link below:
- Watch Bill Nye pushing the bowling ball too far at the link below:
Why It Matters
- The conservation of energy in physics states that in an isolated system, the total change in energy is equal to zero. This leads to the conclusion that the total energy of the universe is constant. While the energy can be converted from one form to another: mechanical to thermal or kinetic to potential, the total energy is constant. Mathematically this is represented as:
The conservation of energy is used in almost every facet of our life:
- Mechanical energy is converted to thermal energy in the process of using the breaks on an automobile.
- Falling water (having potential energy) is used to turn a turbine that creates electricity.
- Releasing a rollercoaster cart from a certain height so the cart will have enough velocity to make it through an upside down loop.
Show What You've Learned
Using the information provided above, answer the following questions.
- Assume you hold a ball from your outstretched arm. When you drop the ball, how much kinetic energy does it have before it strikes the ground if it had 5 J of potential energy before being dropped?
- For the bowling ball scenario described above, where does the ball have the maximum kinetic energy?
- For the bowling ball scenario described above, where are the two points that the bowling ball have the maximum potential energy?