\phi = -45 + \frac{\alpha}{2} - \frac{\beta}{2} The cutting force and thrust force in an orthogonal cutting operation are 1470 N and 700 N, respectively. Rake angle = 7°, width of the cut = 4.0 mm, chip thickness before the cut = 0.3mm, and chip thickness ratio = 0.4. Determine (a) the normal stress on the shear plane and (b) the friction force on the tool-chip interface. You may use Merchant equation: \begin{equation} \tan \phi = \frac{r \cos \alpha}{1 - r \sin \alpha} = \frac{t_o}{t_c} \end{equation}