Chapter 5, Problem 14OQ

An object of mass m is sliding with speed v_i at some instant across a level tabletop, with which its coefficient of kinetic friction is μ. It then moves through a distance d and comes to rest. Which of the following equations for the speed v_i is reasonable?

1. (a) $v_i=\sqrt{-2\mu mgd}$
2. (b) $v_i=\sqrt{2\mu mgd}$
3. (c) $v_i=\sqrt{-2\mu gd}$
4. (d) $v_i=\sqrt{2\mu gd}$
5. (e) $v_i=\sqrt{2\mu d}$