In an ideal orthogonal cutting experiment (see figure), the cutting speed V is 1 m/s. the rake angle of the tool α = 5 degrees, and the shear angle, φ, is known to be 45 degrees. Applying the ideal orthogonal cutting model, consider two shear planes PQ and RS close to each other. As they approach the thin shear zone (shown as a thick line in the figure), plane RS gets sheared with respect to PQ (point R₁ shears to R₂, and S₁ shears to S₂).
Assuming that the perpendicular distance between PQ and RS is δ = 25 µm, what is the value of shear strain rate (in s^-1) that the material undergoes at the shear zone?