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Physics Guru is an online education and competitive examinations preparation portal founded by Manish Verma, an IIT Madras alumnus, providing learning resources for competitive examinations.

The emphasis is on conceptual understanding, analytical thinking and problem solving rather than simply memorising formulas and standard methods.

The objective is to help students understand what they are learning and develop the ability to solve problems they have not seen before.

Plane Engine Failure Quiz

A commercial plane experiences a complete loss of all engine power at an altitude of 35,000 feet (1 km = 3280.84 feet) and an airspeed of 450 knots (1 knot = 1.852 km/h). The Ram Air Turbine (RAT) is immediately deployed and the pilots gets ready for emergency landing.

The RAT is designed to generate 20 kVA of electrical power with power generation efficiency of 85%. Power factor is 0.8 for a typical aircraft electrical system. The aircraft's essential systems require a continuous power supply of 13.5 kW.

The aircraft has an average glide ratio of 15:1 (meaning for every 15 units of horizontal distance covered, it loses 1 unit of altitude).

For how many minutes can the RAT continuously power the essential systems if the aircraft maintains a constant glide until it reaches the ground level for an emergency landing? (Ignore any potential battery backup before touchdown and also ignore RAT after touchdown for this calculation).