Friction isn't measured in terms of speed. It's a force that opposes motion. Here's why:

* Friction is a resistance: It acts against the movement of an object, slowing it down or preventing it from moving at all.

* Speed is a measure of how quickly something moves: It describes how fast an object is traveling, not the force that's acting on it.

Think of it like this:

* Speed: How fast a car is going (e.g., 60 mph).

* Friction: The brakes slowing the car down.

How friction affects speed:

* Reducing speed: Friction causes objects to slow down. The more friction, the faster the object will slow down.

* Preventing motion: Strong enough friction can prevent an object from moving at all (like a book sitting still on a table).

So, while friction doesn't have a "speed," it directly influences the speed of objects by slowing them down or preventing them from moving.