Mathematical and Physical Journal
for High Schools
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Problem P. 4088. (September 2008)

P. 4088. The diameter of the rotor blade of a 1-kg model helicopter is 0.4 m. (The rotor blade rotates about a vertical axis.) Estimate the power of the motor which is able to make the helicopter float at a constant height. The density of air is 1.3 kg/m3, the air drag exerted on the body of the helicopter is 10% of the total weight. Consider the speed of the air moved by the rotor blade constant at the whole surface which is swept by the blade.

(5 pont)

Deadline expired on October 13, 2008.


Statistics:

97 students sent a solution.
5 points:Batki Bálint, Bedics Gábor, Béres Bertold, Bodosi Eszter, Csányi Gergely, Csengeri Béla, Csóré András, Dénes Benjámin, Emroz Khan, Fábik Zoltán, Farkas Martin, Filep Tibor, Győrfi Dávid, Hegedűs Csaba, Hoksza Zsolt, Iván Dávid, Jéhn Zoltán, Kótai Áron, Kovács Márk, Kunsági-Máté Éva, Laczkó Zoltán Balázs, Lászlóffy András, Maknics András, Márkus Bence Gábor, Marosi Csaba, Mayer Martin János, Molontay Roland, Mozsáry László, Nagymihály Márk, Najbauer Eszter Éva, Pálovics Péter, Para Attila, Patartics Bálint, Pázmán Koppány, Pető János, Pinczei Emese, Prok Tamás, Sass Zoltán, Szabó 126 Gergely, Szabó 895 Dávid, Szük Dániel, Tamási Mátyás, Trényi Róbert, Varga 777 Ádám, Zsolczai Viktor.
4 points:52 students.

Problems in Physics of KöMaL, September 2008