A person tosses his car keys on top of his dresser with an initial velocity of 2.0m/s. How far will the keys slide across the dresser if the coefficient of the kinetic friction between the two surfaces is 0.30?

Well, I would prefer using the energy equations for that.

KE = Work\ Done\ by\ friction

\frac12 mv^2 = Fd

F = \mu R

R = mg

And from there, you get:

\frac12 mv^2 = \mu mgd

You have v, the initial velocity, you have mu, the coefficient of friction and you have g, the acceleration due to gravity. Find d :)

Thank you! (: