1 horsepower is equal to 746 W, so the power of the engine is
The power is also defined as the energy E per unit of time t:
Where the energy corresponds to the work done by the engine, which is
. Re-arranging the formula, we can calculate the time t needed to do this amount of work:
1 because the the mid night summer is dark
Answer:
Well the reason that elephants have big ears in the first place is to cool off. They flap their ears and use them as fans.
Total energy =kinetic energy +potential energy
Change in energy =change in (kinetic energy +potential energy)
potential energy, 
where m is the mass, g is acceleration due to gravity and h is the height.
potential energy per unit mass =gh
change in potential energy per unit mass = 
where, h is the height.
kinetic energy= 
change in kinetic energy per unit mass,
In the given question:
Height varies from 90 m to zero as river flows from 90 m height to lake at 0 m
Velocity varies from 3m/s at top to o m/s at bottom.
Therefore,
Here, it was mentioned in the question internal energy of the water is constant and there is no change in the pressure at the inlet and outlet.
