How It Works
Bungee jump

The physics behind bungee jumping

Bungee jump

Bungee jump

We are taught that everything falls towards Earth with the same acceleration of g = 9.8 metres (32.2 feet) per square second – ignoring air resistance. However, a bungee jumper often accelerates much faster than this. Of course, this depends on variables like the tension in the cord, as well as the weight of the cord and jumper.

This phenomenon can be visualised by dropping a Slinky and a ball at the same time. Hold the Slinky, letting it hang but not touching the floor. The ball should be level with the top of the Slinky. Release both of them at the same time and watch as the top of the Slinky descends faster than the ball. The top of the Slinky not only accelerates due to gravity, but has a tension force from being stretched, also pulling down on it.

A bungee cord stretches under its own weight as it hangs. So when someone jumps, they are pulled down not just by the force of gravity but by the tension in the cord as well.

Answered by Rik Sargent