Reducing soil resistance through pointed shape

Steps:

• Identify the problem: Hammering requires overcoming soil friction and compression at the post's base.
• Consider force application: The hammer drives the post downward, so the bottom end contacts the ground first.
• Evaluate shapes: A pointed bottom minimizes contact area, concentrating force to penetrate easier.
• Compare options: Only altering the bottom aids entry; other changes increase resistance or don't help.

Why A is correct:

• Pointing the bottom reduces contact area, increasing pressure (P = F/A) to break soil bonds more effectively.

Why the others are wrong:

• B: Top shape affects hammer impact, not ground penetration.
• C: Longer post adds weight but increases total resistance without aiding entry.
• D: Wider post enlarges contact area, decreasing pressure and making it harder.

Final answer: A