In a recent airline disaster, an airliner ying at 30,000ft,550mi/h, lost power and fell to earth. the mass of the aircraft was 255,000 lb. if the magnitude of the work done by drag force on the plane during the fall was 2.96 × 106 btu, estimate the velocity of the aircraft at the time of impact, in mi/h. let g = 32.08 ft/s2.

To develop this problem we will apply the energy conservation theorem and the principle of work. Basically we will have that the kinetic, potential and work energy must be equivalent to the kinetic energy just before the impact. We will start converting the units given to the British system and then proceed with the Calculations.

Remember that according to the energy balance in this case it would be balanced like this

Here

m = mass

= Velocity at each moment

= Work by drag

h = Height

g = Acceleration due to gravity

Mass

Initial Velocity

Work by drag

By work energy principle

Replacing,

Solving for , we have that

Converting this value,

Therefore the velocity of the aircraft at the time of impact is 962.85mi/h

explanation: magnetic pole, region at each end of a magnet where the external magnetic field is strongest. the south-seeking pole, or any pole similar to it, is called a south magnetic pole. unlike poles of different magnets attract each other; like poles repel each other.