calculate friction angle in a machining operation

Question

In an orthogonal cutting test on mild steel, the following data were obtained

Cutting speed : 40 m/min,

Depth of cut : 0.3 mm

Tool rake angle: =5⁰,

Chip thickness: 1.5 mm,

Cutting force: 900 N

Thrust force: 450 N

Using Merchant’s analysis, the Friction angle during the machining will be

(a) 26.5⁰                 (b) 31.5⁰                  (c) 45⁰             (d) 63.40