Consider the following statements
During the third stage of tool-wear, rapid deterioration of tool edge takes place because
$$1.$$ Flank wear is only marginal.
$$2.$$ Flank wear is large.
$$3.$$ Temperature of the tool increases gradually.
$$4.$$ Temperature of the tool increases drastically.

Which of the statements given above are correct?

The following data relate to an orthogonal turning process:
$$\,\,\,\,\,\,\,\,\,\,\,$$Back rake angle $$=15deg,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Width of cut $$=2mm,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Chip thickness $$=0.4mm,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Feed rate $$=0.2mm/rev.$$

If the cutting force and the thrust force are $$900N$$ and $$810N,$$ the mean strength in $$Mpa$$

A batch of $$500$$ jobs of diameter $$50$$ $$mm$$ and length $$100$$ $$mm$$ is to be turned at $$200$$ $$rev/min$$ and feed $$0.2$$ $$mm/rev.$$

Applying Taylor's equation $$V{T^{0.25}} = 160,$$ the tool life in minutes is

The following data relate to an orthogonal turning process:
$$\,\,\,\,\,\,\,\,\,\,\,$$Back rake angle $$=15deg,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Width of cut $$=2mm,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Chip thickness $$=0.4mm,$$
$$\,\,\,\,\,\,\,\,\,\,\,$$Feed rate $$=0.2mm/rev.$$

The shear angle is