# Suppose you are blowing a spherical bubble, filling it in with air at a uniform rate of 400mm^3/s. How fast is the radius of the bubble increasing by the time it is already 20mm long?

##### 1 Answer

Apr 4, 2018

#### Explanation:

if

differentiate both sides with respect to time:

volume of air increasing at uniform rate of 400mm^3/s =

substitute: