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# Problem P. 4851. (May 2016)

P. 4851. In aerodynamics the Mach number is the ratio of the speed of the object moving in air and the local speed of sound.

During a fighter aircraft training one of the fighters ascends from a region of $\displaystyle 0~{}^\circ$C air at a height of some kilometres, while its speed increases from 1.5 Mach to 1.75 Mach. Due to the jet powered engine the fighter's kinetic energy increased by 20%, and its mass decreased by 1%.

$\displaystyle a)$ What is the temperature of the air (in $\displaystyle {}^\circ$C) at the height to which the fighter moved?

$\displaystyle b)$ How much did the fighter ascend, and what is its final speed if the temperature of the air decreases $\displaystyle 0.65~{}^\circ$ in each 100 m increase in height?

(5 pont)

Deadline expired on June 10, 2016.

### Statistics:

 47 students sent a solution. 5 points: Asztalos Bogdán, Balogh Menyhért, Bánki Bence, Bartók Imre, Bekes Nándor, Bukor Benedek, Büki Máté, Csire Roland, Csorba Benjámin, Csuha Boglárka, Debreczeni Tibor, Édes Lili, Fajszi Bulcsú, Fehér 169 Szilveszter, Fekete Balázs Attila, Forrai Botond, Hajnal Dániel Konrád, Iván Balázs, Kasza Bence, Kavas Katalin, Kovács Péter Tamás, Körmöczi Dávid, Krasznai Anna, Mány Bence, Marozsák Tóbiás , Molnár Mátyás, Németh 777 Róbert, Németh Flóra Boróka, Olosz Adél, Páhoki Tamás, Paulovics Péter, Pázmán Előd, Póta Balázs, Pszota Máté, Sal Kristóf, Sallai Krisztina, Szentivánszki Soma , Tibay Álmos, Tófalusi Ádám, Tomcsányi Gergely, Tóth 111 Máté , Varga-Umbrich Eszter, Zöllner András. 4 points: Makovsky Mihály, Wiandt Péter. 3 points: 1 student. 1 point: 1 student.

Problems in Physics of KöMaL, May 2016