A rectangular hole of size 100 mm × 50 mm is to be made

A rectangular hole of size 100 mm × 50 mm is to be made on a 5 mm thick sheet of steel having ultimate tensile strength and shear strength of 500 MPa and 300 MPa, respectively. The hole is made by punching process. Neglecting the effect of clearance, the punching force (in kN) is

Perimeter = (50 + 100) × 2 = 300 , Thickness = 5
so shown Area = 300 × 5 = 1500 mm².
Punching force = τ × A_s = 300 × 1500 = 450 KN