**Problem 115**

What force is required to punch a 20-mm-diameter hole in a plate that is 25 mm thick? The shear strength is 350 MN/m^{2}.

**Solution 115**

The resisting area is the shaded area along the perimeter and the shear force $V$ is equal to the punching force $P$.

$V = \tau A$

$P = 350 \,[ \, \pi (20)(25) \, ]$

$P = 549\,778.7 \, \text{N}$

$P = 549.8 \, \text{kN}$ *answer*