A 100-mm-wide by 8-mm-thick steel bar is transmitting an axial tensile load of 3,000 N. After the load is applied, a 4-mmdiameter hole is drilled through the bar, as shown in Figure P5.70. The hole is...

A 100-mm-wide by 8-mm-thick steel bar is transmitting an axial tensile load of 3,000 N. After the load is applied, a 4-mmdiameter hole is drilled through the bar, as shown in Figure P5.70. The hole is centered in the bar.

(a) Determine the stress at point A (on the edge of the hole) in the bar before and after the hole is drilled.

(b) Does the axial stress at point B on the edge of the bar increase or decrease as the hole is drilled? Explain.