Casting is done by pouring liquid metal into the pouring cup of a sand mold. It was found that the liquidmetal is flowing from the pouring cup into the downsprue with a flow rate of 0.025 kg/sec. At the topwhere the pouring cup leads into the downsprue, the cross-sectional area is 75.0 mm2 and the length of thesprue is 18 cm. Determine:

a. the area at the bottom of the downsprue to avoid aspiration, and

b. the time required to fill the mold cavity, if the volume of the casting is 30000 mm3.

c. Check if flow is fully turbulent, laminar, or mixed at the bottom of sprue and suggest changes tothe sprue design if it needs to.

(metal viscosity = 1.499 10-3 N s/m, and metal density = 2700 kg/m3)