The life of a ball bearing at a load of $$10$$ $$kN$$ is $$8000$$ hours. Its life in hours, if the load is increased to $$20$$ $$kN,$$ keeping all other conditions same, is

Disposable patterns are made of

Two castings, a cube and a slab of the same material solidify under identical conditions. The volumes of the castings are equal but the slab dimensions are in the ratio of $$1:2:4$$, find the ratio of the solidification times of the cube to that of the slab.

A cylindrical billet of $$100$$ $$mm$$ diameter is forged from $$50$$ $$mm$$ height to $$40$$ $$mm$$ at $${1000^0}$$$$C$$. The material has constant flow stress of $$80$$ $$MPa.$$ Find the work of deformation. If a $$10$$ $$kN$$ drop hamper is used to complete the reduction in one blow. What will be the height of fall.