Question

After a “Mueller mechanical integrating” type of these devices was discovered in an unexploded V-2 rocket, Charles Stark Draper adapted it into a type still used in modern missiles. (-5[1])Thermal examples of these devices lack moving parts and work by measuring the asymmetry of temperature distribution (-5[1])around a bubble in a sealed space. The GOCE (“GO-chey”) spacecraft contains three pairs of highly accurate (-5[1])examples of these devices to try to find the exact (-5[1])shape of the geoid. (-5[2])MEMS examples of these devices (10[1])consist of a seismic mass and a cantilever beam. (10[1]-5[1])Spring-based examples (10[1])of these devices give a value of (-5[1])[read slowly] “the spring constant times distance moved by a (-5[1])mass, all over the test mass.” (10[1]-5[1])In smartphones, these devices (10[1])can (10[1])trigger (10[2]-5[3])screen rotation by (10[1]-5[2])determining orientation changes. For 10 points, name these devices that measure the rate of change of (10[14]0[1])velocity. ■END■

ANSWER: accelerometers [accept Mueller mechanical integrating accelerometers or pendulous integrating gyroscopic accelerometers or MEMS accelerometers or PIGA accelerometers or gravimeters; prompt on gradiometers; prompt on gyroscopes until “bubble” is read by asking “what other device is the gyroscope a part of?”; reject “gyroscopes” after “bubble” is read]
<Physics>
= Average correct buzz position

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Summary

2025 ACF Nationals04/19/2025Y2496%0%63%126.96

Buzzes

PlayerTeamOpponentBuzz PositionValue
Aidan RoulletRITIllinois B28-5
Qingyu ZhangFloridaNYU45-5
Karan GurazadaTexasCornell A61-5
Jim FanNorth Carolina AColumbia A71-5
Alex AkridgeIndianaIllinois A75-5
Joy AnHarvardToronto B75-5
Jonathan HuangMITToronto C8010
Colin VeeversOttawaWaterloo B8910
June YinWUSTL BPenn State89-5
Swapnil GargUC Berkeley AWaterloo A9110
Joseph ChambersVirginiaMichigan98-5
Roxanne TangOhio StateNorth Carolina B108-5
Sky LiToronto AStanford114-5
Matt SchiavoneNorthwesternWUSTL A11410
Vinu HariharUC Berkeley BArizona State11810
Andrew WangIllinois AIndiana11910
John MarvinChicago ARutgers12010
Conor ThompsonIowa StateVirginia Tech12010
Olin BoseColumbia BMaryland120-5
Thomas TibbettsUCFCornell B120-5
Gavin MarkoffVanderbiltWinona State120-5
Matthew WangBritish ColumbiaLSE123-5
Andres CordobaYaleGeorgia State123-5
Rohan DalalGeorgia TechJohns Hopkins12310
Albert Yingzhi NyangLSEBritish Columbia13910
Liam StarnesChicago BMinnesota13910
Shardul RaoMinnesotaChicago B1390
Richard NiuCornell ATexas13910
Ryan RosenbergNYUFlorida13910
Amogh KulkarniGeorgia StateYale13910
Shardul ParthasarathyIllinois BRIT13910
Isaac MammelMarylandColumbia B13910
Todd MaslykMichiganVirginia13910
Geoffrey WuColumbia ANorth Carolina A13910
Soren HeydariNorth Carolina BOhio State13910
Michał GerasimiukStanfordToronto A13910
Kunaal ChandrashekarToronto BHarvard13910
Yared TadesseCornell BUCF13910
Ani PerumallaPenn StateWUSTL B13910