Q1: The fluid jet discharging from a 2" diameter orifice has a diameter of 1.75" at its vena-contracta. The co-efficient of contraction is

ANS:B - 0.766

The coefficient of contraction CcC_cCc​ for a fluid jet is defined as the ratio of the diameter of the vena contracta to the diameter of the orifice from which the jet emerges. Given:

• Diameter of the orifice, D1=2D_1 = 2D1​=2 inches
• Diameter of the vena contracta, D2=1.75D_2 = 1.75D2​=1.75 inches

The coefficient of contraction CcC_cCc​ is calculated as: Cc=D2D1=1.752=0.875C_c = \frac{D_2}{D_1} = \frac{1.75}{2} = 0.875Cc​=D1​D2​​=21.75​=0.875 Therefore, the coefficient of contraction CcC_cCc​ is approximately 0.8750.8750.875. Among the options provided:

• 1.3
• 0.766
• 0.87
• none of these

The closest match to our calculated value 0.8750.8750.875 is 0.870.870.87. So, the correct answer is: 0.87\boxed{0.87}0.87​