Question

In sand casting of the hollow part of lead, a cylindrical core of diameter 120 mm and height 180 mm is placed inside the mould cavity. The densities of core material and lead are 1600 $kg/m^3$ and 11300 $kg/m^3$ respectively. The net force (in N) that tends to lift the core during pouring of molten metal will be

• A. $257.6$
• B. $193.7$
• C. $64.5$
• D. $19.7$

Answer 1

The correct option is B $193.7$

$\text{Net force acting on core =}(\rho -\sigma )gV$

Where

$V=\frac{\pi }{4}\times {120}^2\times 180$

$=2035752m{m}^3=2.035\times {10}^{-3}{m}^3$

$\therefore \text{Net force = (11300-1600)×9.81×2.035×(}{10}^{-3}\text{)}$

$\text{= 193.71 N}$