Question

A sprue in a sand mould has a top diameter of 20 mm and height of 200 mm. The velocity of the molten metal at the entry of the sprue is 0.5 m/s. Assume acceleration due to gravity as 9.8 $m/s^2$ and neglect all losses. If the mould is well ventilated, the velocity (upto 3 decimal points accuracy) of the molten metal at the bottom of the sprue is m/s

• A. 2.043

Answer 1

The correct option is A 2.043
Given:

$h_s=200mm,u_2=0.5m/s,$

$g=9.8m/s^2;d_2=20mm$

$u_3=?$

$u_2=\sqrt{2g{h}_c}$

$0.5=\sqrt{2\times 9.81\times h_c}$

$\Rightarrow h_c=0.01274m$

$h_t=h_s+h_c=0.200+0.01274$

$\text{= 0.2127 m}$

$u_3=\sqrt{2g{h}_t}=\sqrt{2\times 9.81\times 0.2127}$

$u_3=2.043m/s$