Terminology for conventional impression die forging

Q. A solid cylinder of diameter 100 mm and height 50 mm is forged between two frictionless flat dies to a height of 25 mm. The percentage change in diameter is

1. 0
2. 2.07
3. 20.7
4. 41.4

Q. In open-die forging, a disc of diameter 200 mm and height 60 mm is compressed without any barreling effect. The final diameter of the disc is 400 mm. The true strain is

1. 1.986
2. 1.686
3. 1.386
4. 0.602

Q.

The radius of a cylinder is increasing at a rate of $3$ $\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$sec$}\right.$ and its altitude is decreasing at a rate of $4\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$sec$}\right.$.

The rate of change of volume when radius is $4m$ and altitude is $6m$ is

1. $80\mathrm{\pi }\raisebox{1ex}{${\mathrm{m}}^3$}\!\left/ \!\raisebox{-1ex}{$\sec $}\right.$

2. $144\mathrm{\pi }\raisebox{1ex}{${\mathrm{m}}^3$}\!\left/ \!\raisebox{-1ex}{$\sec $}\right.$

3. $80\raisebox{1ex}{${\mathrm{m}}^3$}\!\left/ \!\raisebox{-1ex}{$\sec $}\right.$

4. $60\raisebox{1ex}{${\mathrm{m}}^3$}\!\left/ \!\raisebox{-1ex}{$\sec $}\right.$