The specific metal cutting energy is expressed as
where '$$\alpha$$' is rake angle, '$$\beta$$' is friction angle, '$$\phi$$' is shear angle and '$$\tau$$' shear stress

A

$$\frac{\tau \cos(\beta - \alpha)}{\sin \phi \cos (\phi + \beta - \alpha)}$$

B

$$\frac{\tau \sin(\beta - \alpha)}{\sin \phi \cos (\phi - \beta + \alpha)}$$

C

$$\frac{\tau \cos(\alpha - \beta)}{\sin \phi \cos (\phi - \beta + \alpha)}$$

D

$$\frac{\tau \sin(\alpha - \beta)}{\sin \phi \cos (\phi + \beta - \alpha)}$$