Understand the relationship between centrifugal acceleration and rotational speed by studying a wringer
Astronauts and spinners
By studying the practical case of a smartphone placed in a salad spinner, the student calculates the relationship between rotation and centrifugal acceleration. There will also be questions about the measurement limits of the instruments.
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Sample protocol for the student
1. In the film The Right Stuff, the astronauts are subjected to stress tests. Try to understand these tests with a salad spinner
2. To be sure that the astronauts withstand high accelerations, they are subjected to the centrifuge test
3. In this test, a capsule in which the astronaut is fitted turns faster and faster around an axis until he passes out or asks to stop
4. A human who is not trained supports an acceleration of 4 to 6 g, i.e. 4 to 6 times its weight. An astronaut can support up to 12 g
5. With the help of your smartphone and a salad spinner, can you reproduce a centrifuge and measure the maximum acceleration to which you can submit your mobile?
6. Don't forget to pack your smartphone well!
7. Would an astronaut have survived if it were instead of your smartphone in the basket?
8. Can you calculate and verify experimentally the rotation speed of the spinner's basket for this acceleration?
9. If the basket is larger, but spins at the same speed, will the acceleration be greater or less?
10. What do you infer about the design of a centrifuge?
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