The friction losses through a 10.0 km horizontal pipe of a certain diameter is given by the relation   = 0.005 L where is the head loss due to friction and L is the length of the pipe. The total...

The friction losses through a 10.0 km horizontal pipe of a certain diameter is given by the relation

  = 0.005 L

where
is the head loss due to friction and L is the length of the pipe. The total energy head at the end of the pipe is 21.0 m. Estimate the total energy head at the pipe inlet.