ID: Class: 12Subject: MathTopic: Application of DerivativeType: Short
Question:
The radius of an air bubble is increasing at the rate of \(\dfrac{1}{2}\;{\text{cm}}/{\text{s}}\). At what rate is the volume of the bubble increasing when the radius is \(1\;{\text{cm}}\) ?
Official Solution
Explanation:
We are given that the radius of an air bubble is increasing at the rate of \(\frac{1}{2}\) cm/s. We want to find the rate at which the volume of the bubble is increasing when the radius is 1 cm.
Assuming the bubble is spherical, the volume is given by: \[V = \frac{4}{3}\pi r^3\]
Differentiating both sides with respect to time \(t\): \[\frac{dV}{dt} = \frac{d}{dt}\left(\frac{4}{3}\pi r^3\right) = \frac{d}{dr}\left(\frac{4}{3}\pi r^3\right) \cdot \frac{dr}{dt} = 4\pi r^2 \cdot \frac{dr}{dt}\]