Question
The “static” type of this quantity applies in the case of a stationary particle on an inclined plane. For 10 points each:
[10e] What dimensionless quantity, often denoted by the letter mu, is very low for materials displaying superlubricity?
ANSWER: coefficient of friction [accept static coefficient of friction]
[10m] [read slowly] If the coefficient of friction between the particle and the plane is “one over root 3,” then what is the maximum inclination of the plane to the horizontal for which the particle can stay in equilibrium in the absence of external forces? You have 10 seconds.
ANSWER: 30 degrees [or pi over 6 radians or one-sixth pi radians] (The maximum angle is given by the arctangent of the coefficient of friction.)
[10h] The angles between the forces acting on the particle are related by this French mathematician’s namesake theorem based on the sine rule. He stated the parallelogram law of forces around the same time as Isaac Newton and Pierre Varignon (“vah-rin-YON”).
ANSWER: Bernard Lamy [or Bernard Lami; accept Lami’s theorem]
<Physics>
Summary
| 2024 ACF Nationals | 2024-04-21 | Y | 24 | 16.25 | 92% | 67% | 4% |
Data
| Brown | Berkeley A | 10 | 0 | 0 | 10 |
| Chicago A | North Carolina A | 10 | 0 | 0 | 10 |
| North Carolina B | Chicago C | 10 | 10 | 0 | 20 |
| Claremont Colleges | Rutgers | 10 | 10 | 0 | 20 |
| WUSTL A | Columbia A | 10 | 10 | 10 | 30 |
| Columbia B | Ottawa | 10 | 10 | 0 | 20 |
| Georgia Tech | Michigan | 10 | 0 | 0 | 10 |
| Indiana | Stanford | 10 | 10 | 0 | 20 |
| Illinois | Johns Hopkins | 0 | 10 | 0 | 10 |
| Cornell B | Kentucky | 10 | 0 | 0 | 10 |
| Maryland | NYU | 10 | 10 | 0 | 20 |
| Harvard | McGill | 10 | 0 | 0 | 10 |
| Cornell A | Minnesota A | 10 | 0 | 0 | 10 |
| Truman State | Minnesota B | 10 | 10 | 0 | 20 |
| Purdue | Chicago B | 10 | 10 | 0 | 20 |
| South Carolina | Chicago D | 0 | 10 | 0 | 10 |
| Northwestern | Toronto A | 10 | 10 | 0 | 20 |
| Arizona State | Toronto B | 10 | 0 | 0 | 10 |
| Berkeley B | Vanderbilt | 10 | 10 | 0 | 20 |
| Penn | Virginia | 10 | 10 | 0 | 20 |
| Florida | WUSTL B | 10 | 10 | 0 | 20 |
| Waterloo | Texas | 10 | 10 | 0 | 20 |
| Yale A | Iowa State | 10 | 0 | 0 | 10 |
| Yale B | Duke | 10 | 10 | 0 | 20 |