Parachute Drop

Jump out of a plane! Choose how you fall, when to open your parachute and how big it is, then watch your speed on the graph.

Falling position
Parachute size
Playback speed
Height
3000 m
Speed
0.0 m/s
Time
0.0 s
Terminal velocity
55.2 m/s
Air resistance
0 N
Opening jolt
5.1 g

The maths, live

Weight W = m × gW = 80 × 9.81 = 785 N
Air resistance F = ½ × ρ × Cd·A × v²F = ½ × 1.2 × 0.43 × 0.0² = 0 N
Terminal velocity (F = W) v = √(2mg ÷ ρCd·A)v = √(2 × 80 × 9.81 ÷ (1.2 × 0.43)) = 55.2 m/s
Net force F = W − air resistanceF = 785 − 0 = 785 N

Watch the graph flatten out: when air resistance grows as big as your weight, you stop speeding up. That is terminal velocity.

How it works

As you fall faster, the air pushes back harder. Air resistance grows with the square of your speed: F = ½ × ρ × Cd·A × v². When it grows as big as your weight, the forces are balanced, you stop speeding up and fall at a steady speed called terminal velocity. A skydiver lying belly down reaches about 55 m/s (200 km/h).

Opening the parachute makes the area facing the air much bigger, so air resistance is suddenly much larger than your weight. The net force points upwards and you slow down, until air resistance matches your weight again at a new, gentle terminal velocity of about 5 m/s.

Try this

  1. Jump belly down, then head down. Which has the bigger terminal velocity?
  2. Try the small parachute. How fast do you land? What about the large one?
  3. Look at the graph just after the parachute opens. Why does the line drop so steeply?