An orthogonal turning operation is carried out under the following conditions: rake angle = $5^{\circ}$; spindle rotational speed = $400 \text{ rpm}$; axial feed = $0.4 \text{ m/min}$ and radial depth of cut = $5 \text{ mm}$. The chip thickness, $t_c$, is found to be $3 \text{ mm}$. The shear angle (in degrees) in this turning process is_____