- #1
Jamin2112
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Homework Statement
A spherical raindrop evaporates at a rate proportional to its surface area. Write a differential equation for the volume of the raindrop as a function of time.
Homework Equations
V = (4/3)πr3
S=4πr2
The Attempt at a Solution
dV/dt = -k(4πr2), k>0
Therefore dV/dt = -k(3/r)V
But the answer in the back of the book is
-kV2/3
How did they get that?