A 10 kg box needs 40 N to start moving on a floor. The coefficient of static friction is 0.4. How can we reduce the effort? Method 1 — Wheels: Put the box on a trolley. Rolling friction μ ≈ 0.02. New force = 0.02 × 10 × 9.8 = 1.96 N. Effort drops from 40 N to ~2 N! Method 2 — Lubrication: Oil the surface. μ drops from 0.4 to 0.1. New force = 0.1 × 10 × 9.8 = 9.8 N. Method 3 — Streamlining/Air cushion: Use an air hockey style cushion — nearly zero friction. Answer: Wheels are best — effort drops by 95%.