During orthogonal turning by using a single point cutting tool, feed rate is $0.24 \mathrm{~mm} / \mathrm{rev}$. The uncut chip thickness is 0.23 mm . The shear angle, tangential force component, and radial force component are $20^{\circ}, 800 \mathrm{~N}$, and 150 N , respectively. The value of shear force is $\_\_\_\_$ N (rounded off to 2 decimal places).

A drill bit during its lifetime can produce 150 through holes in a plate at a drill-speed of 200 RPM . If the drill-speed increases to 300 RPM , then it can produce 60 through holes in the same plate before the drill bit fails. Assume all other parameters remain constant. The value of the exponent in Taylor's tool life equation is $\_\_\_\_$ (rounded off to 2 decimal places).

A cutting tool provides a tool life of 60 minutes while machining with the cutting speed of 60 m/min. When the same tool is used for machining the same material, it provides a tool life of 10 minutes for a cutting speed of 100 m/min. If the cutting speed is changed to 80 m/min for the same tool and work material combination, the tool life computed using Taylor’s tool life model is _______ minutes (rounded off to 2 decimal places).

In an ideal orthogonal cutting experiment (see figure), the cutting speed V is 1 m/s, the rake angle of the tool α = 5°, and the shear angle, 𝜙, is known to be 45°.

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?