# Using Impulse vs Force

Looking at the documentation and also the differences between “force” and “impulse” it seems these are nearly identical.

Impulse:

An impulse is a force applied to a body in an instance which will change the current linear velocity and/or the angular velocity of the body

Applied Force:

An applied force will only affect the body over the time period that it is applied which is the duration of the frame interval.

If I understand correctly the force would last longer whereas an impulse would happen instantly. Are there some common examples of how you would use one over the other?

So would an impulse be used for something like an explosion or something popping up? Applied force could be used to propel a rocket over a few seconds?

Let me add @Cedric

The difference is an impulse a applied to the body independly of time:

``````velocity += impulse / body_mass
``````

Whereas force is applied per timestep

``````velocity += (force / body_mass) * delta_time
``````

In practice, if you want to do an explosion, you use an impulse once. If you want to steer a wheel, you add a force each frame.

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Thank you, that confirms what I thought.

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