12. (A) (SI units) A low-carbon steel plate is 270 mm wide and 25 mm thick. It is reduced in one pass in a two-high rolling mill to a thickness

of 20 mm. Roll radius = 600 mm, and roll speed =30 m/min. Strength coefficient = 500 MPa, and strain hardening exponent = 0.25. Determine the (a) roll force and (b) roll torque. (6').