Question

A side riser is to be designed for a hollow cylindrical casting of 50 mm inside diameter and 100 mm outside diameter. If the length of cylinder is 50 mm, the diameter of riser in mm is _____ .

• A. 59
• B. 60
• C. 70
• D. 49

Answer 1

The correct option is B 60

$M_r=1.2M_c$

$M_r$ = modulus of riser

$=\frac{\text{Volume of riser}}{\text{Surface area}}=\frac{D}{6}$

$\frac{D}{6}=1.2M_c$

$\frac{D}{6}=\frac{1.2\times \frac{\pi }{4}({100}^2-{50}^2)\times 50}{2\times \frac{\pi }{4}({100}^2-{50}^2)+\pi (100+50)\times 50}$

$\Rightarrow$ D = 60 mm