Question

What what work is done when an aeroplane changes its speed from 180 km per hour to 270 kilometre per hour take the mass of the aeroplane 20000 kg

Answer 1

Answer:

work done = change in KE = 3125KJ = 3125000J

Explanation:

First law of thermodynamics = The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed

Final Velocity = 270kmph = 75ms-1

Initial Velocity = 180kmph = 50ms-1

so amount of work done =  change in KE + change in PE

there is not change in PE

so

amount of work done =  change in KE

$KE = \frac{1}{2}mv^{2}$

Change in KE

$=\frac{1}{2}m(v_{2}^{2} - v^{2}_{1})\\=  \frac{1}{2}*2000*(75^{2} - 50^{2})$

work done = change in KE = 3125KJ

Answer 2

Answer:

work done = change in KE = 3125KJ = 3125000J

Explanation:

First law of thermodynamics = The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed

Final Velocity = 270kmph = 75ms-1

Initial Velocity = 180kmph = 50ms-1

so amount of work done =  change in KE + change in PE

there is not change in PE

so

amount of work done =  change in KE

Change in KE

work done = change in KE = 3125KJ

Explanation: