Question

The force required to punch a **** of 2 cm square in a steel sheet 2 mm thick whose shearing strength is 3.5 x 108 N/m2 will be

(a) 7 x 104 N

(b) 5.6 x 104 N

(c) 1.4 x 104 N

(d) 0.875 x 104 N

Answer 1

The correct option is (b) 5.6 x 104 N.

Explanation:

The shearing stress is exerted on the rectangular surface (2 cm x 0.2 cm) that is the boundary of the ****. The area of this surface

A = 2 x 10-2 x 4 x 0.2 x 10-2 m2

= 1.6 x 10-4 m2

Minimum shearing stress to rupture the steel sheet

= (F/A)min = 3.5 x 108 N/m2

Force = 3.5 x 108 x 1.6 x 10-4

= 5.6 x 104 N