I'm sorry that I can only give the question here but I have no idea how to calculate $\mu$. Question is as follows:
A body is projected at $24\text{ft/sec}$ up a rough plane inclined at $\text{tan}^{-1} \frac{7} {24} $ to the horizontal. With what velocity does it return to the point of projection?
Despite several attempts, I have been unable to calculate $\mu$ and therefore can not find retardation or acceleration. I have tried looking at the point where instantaneous velocity is zero but if I take retardation and acceleration as zero at this point then I end up in a bit of a pickle! If anyone can offer any helpful advice/hints then I would be extremely grateful.