Three castings are of the same material, volume and cast under similar conditions. One is a sphere, another is a cube and the third is cylinder with its length being equal to its diameter.

The ratio of solidification times of sphere to the cube is

Shell molding is an investment casting process $$(T/F)$$

Given
$$y = \int\limits_1^{{x^2}} {\cos t\,\,\,dt,} $$ $${\,\,\,}$$ then $${{dy} \over {dx}} = \_\_\_\_\_.$$

Two plates with symmetrical $$V$$ joint penetration of $$V$$ angle $$60deg$$ are to be arc welded in a single pass. The power $$P(kW)$$-arc length $$L$$ $$(mm)$$ characteristic is given by $$P=4+0.8L-0.1$$$${L^2}$$. Assuming that the top surface of the weld is flat & flush with the plate top surface, & the energy losses are $$20\% $$, the density of filler material is $$8gm/cc$$ and the energy required to melt $$1$$ $$gm$$ is $$1400$$ joules. The plate dimensions are $$1000mm$$ length & $$5mm$$ thickness. The maximum welding speed is .......................