Centripetal Force Demonstration

Centripetal Force Demonstration

CHIN
Canadian Heritage Information Network, Canada Museum of Science and Technology, Musée de la civilisation, Stewart Museum, Canadian Medical Hall of Fame, Museum of Health Care at Kingston, University Health Network Artifact Collection, University of Toronto Museum of Scientific Instruments, University of Toronto Museum Studies Program, Suzanne Board, Dr. Randall C. Brooks, Sylvie Toupin, Ana-Laura Baz, Jean-François Gauvin, Betsy Little, Paola Poletto, Dr. James Low, David Kasserra, Kathryn Rumbold, David Pantalony, Dr. Thierry Ruddel, Kim Svendsen


Transcript

Do you remember how it feels when you are firmly seated in a roller coaster car and the car starts to move? What keeps you from falling out in the loop? Let’s start from the beginning… When the car is released from the top left, it gains constant horizontal speed due to the initial impulse. Gravity gives it a vertical acceleration as it descends down the slope. As a result, the car has a greater speed at the bottom of the slope than it had at the start. It is during this fall that you as a passenger experience a feeling of being lighter than you are. Then, when the car changes direction as it enters the loop, you feel squashed into the seat. This is due to inertia and the centripetal force (a force felt by any body moving in curve or circle, and directed towards the centre of the curve). Inertia (a law of nature) refers to the inclination of any moving body to travel in a straight line. In this case, the force of the rail keeps you and the car from continuing in a straight line and impels you into the curve. It is the rail that is responsible for the centripetal force on the car, acting in a direction towards the centre of the loop. The combination of inertia, gravity, centripetal force, and friction determine if you will (or will not!) successfully complete your roller coaster ride. To prevent the car from falling out in the loop, its speed before entering the loop has to be sufficiently fast to prevent gravity from significantly affecting the trajectory of the car and thus pull it from the rail… hence the importance of achieving enough speed before entering the loop. This high speed can be achieved in two ways. Either by giving the car a strong push at the start, which requires a lot of energy, or by using the force of gravity on a slope before the loop. The second option is generally preferred.


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