The force $${F_1}$$ and $${F_2}$$ in a brake band and the direction of rotation of the drum are as shown in the figure. The coefficient of friction is $$0.25.$$ The angle of wrap is $$3\pi /2$$ radians. It is given that $$R=1$$ $$m$$ and $${F_2} = 1N.$$ The torque (in $$N-m$$) exerted on the drum is ____________

The welding process which uses a blanket of fusible granular flux is

Gray cast iron blocks of size $$100\,\,mm \times 50\,\,mm \times 10\,\,mm$$ with a central spherical cavity of diameter $$4$$ mm are sand cast. The shrinkage allowance for the pattern is $$3\% $$. The ratio of the volume of the pattern to volume of the casting is ___________________

The value of true strain produced in compressing a cylinder to half its original length is