Question

A casting of dimension $200\times 100\times 60$ mm is casted in such a way that 60 mm dimension is vertical and 2/3${}^{rd}$ of it is in drag. If the height of the cope is 100 mm and the cavity is fed by a bottom gate with a cross sectional area 100 mm${}^2$, the time (seconds) taken to fill the cavity is ________ .

• A. 99
• B. 89
• C. 75.6
• D. 82.47

Answer 1

The correct option is D 82.47


$\frac{volume}{time}=A\times V$

Volume = $200\times 100\times 60=1200000m{m}^3$

A = 100 mm ${}^2$

$V=\frac{V_{max}+V_{min}}{2}$

V = $\frac{\sqrt{2g\times h_{max}}+\sqrt{2g{h}_{min}}}{2}$

$=\frac{\sqrt{2\times 9810\times 140}+\sqrt{2\times 9810\times 80}}{2}=\frac{1657.34+1252.84}{2}=1455mm/sect=\frac{12000000}{100\times 1455}$

= 82.47 sec