Why Skydivers Don't Keep Getting Faster

💪 Why Skydivers Don't Keep Getting Faster

Figure 1: At terminal velocity the upward air resistance (cyan) exactly balances the downward weight (amber) — equal arrows mean zero resultant force, so the velocity stops changing.

Jump from a plane at 4,000 metres and something remarkable happens. For the first few seconds you accelerate furiously — stomach in your mouth, wind roaring past. But after about 12 seconds you notice something strange: you stop speeding up. You're still falling at roughly 55 m/s (about 120 mph), but the acceleration has gone. You've reached terminal velocity.

The secret is air resistance. The faster you fall, the harder the air pushes back up against you. Eventually the upward air resistance exactly equals your downward weight. At that moment the resultant force becomes zero — and Newton's First Law takes over: no resultant force means no change in velocity. You carry on at a constant, terrifying 55 m/s.

Open your parachute and the game changes instantly. The huge canopy dramatically increases your surface area. Air resistance rockets up, far exceeding your weight. You decelerate sharply until a new, much lower terminal velocity of about 5 m/s is reached — just enough for a safe landing.