Rotating Board (Andrew Salg)
Author
Andrew Salg
Principles
Inertia
Motion
Conservation of momentum
Energy
Standards
HS-PS2-1 Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.
HS-PS2-3 Apply scientific and engineering ideas to design, evaluate, and refine a device that minimizes the force on a macroscopic object during a collision.
Materials needed
Rotating Platform
Bicycle wheel
Procedure
1. Check that there are no problems with the board, and get on the rotating platform. Spin around several times to get a feel of the board.
2. Take a bicycle wheel, and have a person or yourself spin the wheel while you are holding it.
3. Shift the wheel to either you left or right, and make observations on which way you are spinning on the board while the tire is turning.
Explanation
The board is an example of a closed system and what happens is the momentum stays constant in the system. The momentum is shifted in different directions when moving the wheel. Turning the wheel shifts the momentum causing the person on the board to rotate around. This is to the rotation of the wheel turning the energy into motion. Also, using the angular momentum of the wheel a person can either get a greater amount of momentum or lose momentum over time depending on which way the wheel is spinning and being held. The wheel has the desire to corrects itself, so if held as a slight angle a person will feel resistance and momentum shifts from the spinning of the wheel desire to correct itself when moved while standing straight on the board.
Questions
1. What is the difference between linear momentum and angular momentum?
A. Linear momentum is m *v and angular momentum is m*v*r.
2. What type of energy is being produced when an object is in motion?
A. Kinetic energy.
3. In which way does angular momentum apply to your life?
A. Open answer can be anything from bike, cars, to exercising.
4. Why does the board rotate when tire is spinning one way, but not necessarily the other way?
A. The board rotates one way due to the momentum of the tire moving in that direction creating a force to move the board underneath the feet. The board will not always move the other way due to inertia and momentum not moving that way resulting in little or no movement.
Everyday examples of the principles illustrated
Car making a turn, Dancers spinning, planes doing a barrel roll, cycling
Photos
