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# speed

The rate at which the simulation executes.

```
var speed: CGFloat { get set }
```

## Discussion

The default value is `1.0`, which means that the simulation runs at normal speed. A value other than the default changes the rate at which time passes in the physics simulation. For example, a speed value of `2.0` indicates that time in the physics simulation passes twice as fast as the scene’s simulation time. A value of `0.0` pauses the physics simulation.

> Note:
> Increasing the speed of the physics simulation reduces its accuracy.

---

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