A man on a bench will exert the greatest pressure on the bench when he

Analyze the question: The question asks when the man exerts the greatest pressure on the bench. Notice it asks about pressure, not force.

Concept: Pressure is force per unit area:

P = F / A

The force here is the man's weight (W = mg), which stays the same whatever position he takes. So pressure depends only on the contact area:

• Smaller contact area → greater pressure
• Larger contact area → smaller pressure

Solution: Compare the contact area in each position.

• A. Lying flat on his back: very large contact area, so the pressure is very small.
• B. Lying flat on his belly: also a very large contact area, so the pressure is very small.
• C. Standing on both feet: a moderate contact area (two feet).
• D. Standing on the toes of one foot: the smallest contact area, since only the tips of the toes of a single foot touch the bench.

Since the weight is constant, the smallest area gives the greatest pressure.

Answer: D. Stands on the toes of one foot.

Tip: For "greatest pressure" questions, look for the smallest area. For "least pressure" questions, look for the largest area. This is why a sharp knife cuts better than a blunt one, and why high-heeled shoes can dent floors. Don't confuse pressure with force. The force (his weight) is the same in all four cases, and only the area changes.