If your bike wheel of radius 40 cm takes 10s for one complete rotation, what is your bike speed?

8π.

Explanation:

The wheel's radius is 40 cm, so the perimeter of the wheel is 80π cm. ( because perimeter equals 2 * radius * π )

According to the formula :

distance = speed * time

We can know that the distance is perimeter of the wheel ( because when the wheel completes a rotation, it also goes forward a distance of the perimeter ) , now we got : 80π = speed * 10,

so the answer is 8π.

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