Oil with a specific gravity of 0.7 is pumped through a horizontal pipeline of 100 mm diameter, containing an orifice plate with a throat diameter of 40 mm. The pressure drop across the orifice is measured on a U-tube manometer, containing mercury, specific gravity 13.6, and the difference in levels of the columns 45 mm. The coefficient of discharge for the orifice plate is 0.65. With the aid of a free body diagram and deriving an equation using Bernoulli, determine the following; a) Velocity of oil through the pipe b) Mass flow of oil c) The manometer reading if the flow rate were reduced by 50%