Question

Wooden 4 inch x 4 inch x 12 feet wooden posts hold up the deck that comes off the second floor of your house. On the ground level, you decide to drill 1 inch holes in two of the posts in order to hang a hammock. Compared to the other posts, the posts that now hold the hammock...

(a) ...have a lower load bearing capacity because of the stress concentration near the holes.

(b) ...have a higher load bearing capacity because of the stress concentration near the holes.

(c) ...have the same load bearing capacity because both are made of the same material.

(d) ...have a lower load bearing capacity because the notches will act as barriers to dislocation motion.

(e) ...have a higher load bearing capacity because the notches will act as barriers to dislocation motion.

Answer 1

Drilling 1 inch holes in the wooden posts will result in a lower load bearing capacity due to the stress concentration around the holes.

Step-by-step explanation:

The load bearing capacity of wooden posts will decrease if 1 inch holes are drilled into them to hang a hammock. This reduction in capacity is due to the phenomenon known as stress concentration, which occurs near the holes. When a hole is drilled into a material, the stress that would normally be distributed evenly across the cross-section is instead concentrated around the edges of the hole.

This concentration of stress can significantly weaken the structural integrity of the posts, making them less able to support heavy loads compared to the other undrilled posts. The correct statement is (a) lower load bearing capacity because of the stress concentration near the holes.

The posts that now hold the hammock have a lower load bearing capacity because of the stress concentration near the holes. When a hole is drilled in a wooden post, it creates a weak point in the structure. This weak point can lead to stress concentration, which means that the stress is concentrated around the hole. As a result, the post becomes more susceptible to failure under load compared to the other posts without holes.