Originally Posted by

**bobak** I found a question to find an expression for the maximum height that a particle projected vertically with a velocity of u can reach if there is a resistive force acting on it of Kmv newton (where m is the particles mass, v being it velocity and k is a constant) and gravity acting on it as well.

after doing a bit of algebra/calculus i got an answer of

. . . . . $\displaystyle \boxed{ \frac{g}{k^2} ln \left(\frac{g}{ku+g} \right) + \frac{u}{k} }$

What i notice i that my solution i not defined for the case k=0, meaning there is a clearly insonsistent with the solution obtained when no air resistance is accounted for. So is my solution incorrect ?