In an ideal orthogonal cutting experiment (see figure), the cutting speed $V$ is $1 \mathrm{~m} / \mathrm{s}$, the rake angle of the tool $\alpha=5^{\circ}$, and the shear angle, $\phi$, is known to be $45^{\circ}$.
Applying the ideal orthogonal cutting model, consider two shear planes $\text{PQ}$ and $\text{RS}$ close to each other. As they approach the thin shear zone (shown as a thick line in the figure), plane $\text{RS}$ gets sheared with respect to $\text{PQ}$ (point $\text{R1}$ shears to $\text{R2}$, and $\text{S1}$ shears to $\text{S2}$).
Assuming that the perpendicular distance between $\text{PQ}$ and $\text{RS}$ is $\delta=25 \; \mu \mathrm{m}$, what is the value of shear strain rate $\left(\right.$ in $\mathrm{s}^{-1}$ ) that the material undergoes at the shear zone?
- $1.84 \times 10^4$
- $5.20 \times 10^4$
- $0.71 \times 10^4$
- $1.30 \times 10^4$
