108) The force exerted by a moving fluid on an immersed body is directly proportional to the rate of change of momentum due to the presence of the body. This statement is called

109) The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to

110) A flow is called sub-sonic, if the Mach number is

111) The discharge of a depressed nappe is 6 to 7 percent __________ that of a free nappe.

112) Re-entrant or Borda's mouthpiece is an __________ mouthpiece.